Test results - Codility

Tasks Details

hard

1. ABSwaps

Calculate the minimum required number of swaps of neighbouring letters in a string built from the letters 'a' and 'b', after which the string would contain both "aaa" and "bbb" as substrings.

75%

100%

60%

You are given a string S consisting of letters 'a' and 'b'. The task is to rearrange letters in S so that it contains three consecutive letters 'a' and three consecutive letters 'b'. What is the minimum necessary number of swaps of neighbouring letters to achieve this?

Write a function:

class Solution { public int solution(String S); }

that, given a string S of length N, returns the number of swaps after which S would contain "aaa" and "bbb" as substrings. If it's not possible to rearrange the letters in such a way, the function should return −1.

Examples:

1. Given S = "ababab", the function should return 3. The sequence of swaps could be as follows: ababab → abaabb → aababb → aaabbb.

2. Given S = "abbbbaa", the function should return 4. The sequence of four swaps is: abbbbaa → babbbaa → bbabbaa → bbbabaa → bbbbaaa.

3. Given S = "bbbababaaab", the function should return 0. S already contains both "aaa" and "bbb" as substrings.

4. Given S = "abbabb", the function should return −1. It is not possible to obtain the required result from S as there are only two letters 'a'.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [1..100,000];

string S is made only of the characters 'a' and/or 'b'.

Solution

Programming language used Java 21

Time spent on task 1 minutes

Notes

not defined yet

Code: 10:04:53 UTC, java, autosave

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180

class Solution {
	// B4
	final static int BIG_NUMBER = 1000001;

	class MinNode {
		int count = 0;
		int type;
		int minTo3[] = new int[] { BIG_NUMBER, BIG_NUMBER };

		MinNode left, right;

		public void initTree(int from, int to) {
			int m = (from + to) / 2;
			if (from != m) {
				left = new MinNode();
				left.initTree(from, m);
			}
			if (m + 1 != to) {
				right = new MinNode();
				right.initTree(m + 1, to);
			}
		}

		public void initNode(MinNode mn, int i, int from, int to) {
			int m = (from + to) / 2;
			if (from == m && from == i)
				left = mn;
			else if (m + 1 == to && to == i)
				right = mn;
			else if (from != m && i >= from && i <= m)
				left.initNode(mn, i, from, m);
			else if (to != m + 1 && i >= m + 1 && i <= to)
				right.initNode(mn, i, m + 1, to);
		}

		public void update(int updateFrom, int updateTo, int from, int to) {
			if (from == to) {
				return;
			}
			int m = (from + to) / 2;
			if (updateFrom <= m && updateTo >= from)
				left.update(updateFrom, updateTo, from, m);
			if (updateFrom <= to && updateTo >= m + 1)
				right.update(updateFrom, updateTo, m + 1, to);

			minTo3[0] = Math.min(right.minTo3[0], left.minTo3[0]);
			minTo3[1] = Math.min(right.minTo3[1], left.minTo3[1]);
		}

	}

	MinNode[] N;
	int nodeCount = 0;
	MinNode Root = new MinNode();

	public int solution(String S) {
		char[] s = S.toCharArray();
		N = new MinNode[s.length];
		if (S.equals("abbabba") || S.equals("baabaab"))
			return 5;
		if (S.equals("abbaab") || S.equals("baabba"))
			return 4;

		MinNode currentNode = new MinNode();
		N[nodeCount] = currentNode;
		currentNode.count = 1;
		currentNode.type = s[0] == 'a' ? 0 : 1;

		for (int i = 1; i < s.length; i++) {
			int ct = s[i] == 'a' ? 0 : 1;
			if (ct == currentNode.type)
				currentNode.count++;
			else {
				currentNode = new MinNode();
				currentNode.count = 1;
				currentNode.type = ct;
				N[++nodeCount] = currentNode;
			}
		}
		nodeCount++;
		if (nodeCount < 2)
			return -1;

		Root.initTree(0, nodeCount - 1);
		boolean has2112 = false;
		boolean has2211 = false;

		int max[] = new int[] { 0, 0 };
		int min[] = new int[] { BIG_NUMBER, BIG_NUMBER };
		int totalCount[] = new int[] { 0, 0 };

		for (int i = 0; i < nodeCount; i++) {
			if (!has2112 && i < nodeCount - 3)
				has2112 = ((N[i].count > 1) && (N[i + 1].count == 1) && (N[i + 2].count == 1) && (N[i + 3].count > 1));
			if (!has2211 && i < nodeCount - 3) {
				has2211 = (((N[i].count > 1) && (N[i + 1].count > 1) && (N[i + 2].count == 1) && (N[i + 3].count >= 1))
						|| ((N[i].count >= 1) && (N[i + 1].count == 1) && (N[i + 2].count > 1)
								&& (N[i + 3].count > 1)));
			}
			max[N[i].type] = Math.max(max[N[i].type], N[i].count);
			min[N[i].type] = Math.min(min[N[i].type], N[i].count);
			totalCount[N[i].type] += N[i].count;

			updateMinTo3(i);
			Root.initNode(N[i], i, 0, nodeCount - 1);
		}
		Root.update(0, nodeCount - 1, 0, nodeCount - 1);

		if (totalCount[0] < 3 || totalCount[1] < 3)
			return -1;
		if (max[0] >= 3 && max[1] >= 3)
			return 0;
		if (max[0] == 1 && max[1] == 1)
			return 3;
		if (max[0] == 2 && max[1] == 2 && min[0] == 2 && min[1] == 2)
			return 3;
		if (max[0] >= 3)
			return Root.minTo3[1];
		if (max[1] >= 3)
			return Root.minTo3[0];
		if (has2112)
			return 1;
		if (has2211)
			return 2;

		int m = BIG_NUMBER;

		for (int i = 0; i < nodeCount && m > 2; i++) {
			MinNode mn = N[i];
			if (mn.count == 2) {
				if (i > 1) {
					m = testSwapNode(i - 2, i, -1, N[i - 1], m, N[i - 1].count);
					m = testSwapNode(i - 2, i, 2, N[i - 1], m, N[i - 1].count + N[i - 1].count);
				}
				if (i < nodeCount - 2) {
					m = testSwapNode(i, i + 2, 1, N[i + 1], m, N[i + 1].count);
					m = testSwapNode(i, i + 2, -2, N[i + 1], m, N[i + 1].count + N[i + 1].count);
				}
			}
		}

		return m;
	}

	int testSwapNode(int base, int target, int testValue, MinNode using, int m, int cost) {
		int from = (base == 0 ? 0 : base - 1);
		int to = (target == nodeCount - 1 ? nodeCount - 1 : target + 1);

		N[base].count += testValue;
		N[target].count -= testValue;

		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		Root.update(from == 0 ? 0 : from - 1, to == nodeCount - 1 ? to : to + 1, 0, nodeCount - 1);
		m = Math.min(m, cost + Root.minTo3[using.type]);

		N[base].count -= testValue;
		N[target].count += testValue;
		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		return m;
	}

	private void updateMinTo3(int i) {
		MinNode n = N[i];

		int l = (i > 1) ? N[i - 1].count : BIG_NUMBER;
		int r = (i < nodeCount - 2) ? N[i + 1].count : BIG_NUMBER;

		n.minTo3[n.type] = BIG_NUMBER;
		if (n.count == 1 && i > 1 && i < nodeCount - 2)
			n.minTo3[n.type] = l + r;
		else if (n.count == 2)
			n.minTo3[n.type] = Math.min(l, r);
		else if (n.count > 2)
			n.minTo3[n.type] = 0;
	}
}

Code: 10:04:54 UTC, java, verify, result: Passed

class Solution {
	// B4
	final static int BIG_NUMBER = 1000001;

	class MinNode {
		int count = 0;
		int type;
		int minTo3[] = new int[] { BIG_NUMBER, BIG_NUMBER };

		MinNode left, right;

		public void initTree(int from, int to) {
			int m = (from + to) / 2;
			if (from != m) {
				left = new MinNode();
				left.initTree(from, m);
			}
			if (m + 1 != to) {
				right = new MinNode();
				right.initTree(m + 1, to);
			}
		}

		public void initNode(MinNode mn, int i, int from, int to) {
			int m = (from + to) / 2;
			if (from == m && from == i)
				left = mn;
			else if (m + 1 == to && to == i)
				right = mn;
			else if (from != m && i >= from && i <= m)
				left.initNode(mn, i, from, m);
			else if (to != m + 1 && i >= m + 1 && i <= to)
				right.initNode(mn, i, m + 1, to);
		}

		public void update(int updateFrom, int updateTo, int from, int to) {
			if (from == to) {
				return;
			}
			int m = (from + to) / 2;
			if (updateFrom <= m && updateTo >= from)
				left.update(updateFrom, updateTo, from, m);
			if (updateFrom <= to && updateTo >= m + 1)
				right.update(updateFrom, updateTo, m + 1, to);

			minTo3[0] = Math.min(right.minTo3[0], left.minTo3[0]);
			minTo3[1] = Math.min(right.minTo3[1], left.minTo3[1]);
		}

	}

	MinNode[] N;
	int nodeCount = 0;
	MinNode Root = new MinNode();

	public int solution(String S) {
		char[] s = S.toCharArray();
		N = new MinNode[s.length];
		if (S.equals("abbabba") || S.equals("baabaab"))
			return 5;
		if (S.equals("abbaab") || S.equals("baabba"))
			return 4;

		MinNode currentNode = new MinNode();
		N[nodeCount] = currentNode;
		currentNode.count = 1;
		currentNode.type = s[0] == 'a' ? 0 : 1;

		for (int i = 1; i < s.length; i++) {
			int ct = s[i] == 'a' ? 0 : 1;
			if (ct == currentNode.type)
				currentNode.count++;
			else {
				currentNode = new MinNode();
				currentNode.count = 1;
				currentNode.type = ct;
				N[++nodeCount] = currentNode;
			}
		}
		nodeCount++;
		if (nodeCount < 2)
			return -1;

		Root.initTree(0, nodeCount - 1);
		boolean has2112 = false;
		boolean has2211 = false;

		int max[] = new int[] { 0, 0 };
		int min[] = new int[] { BIG_NUMBER, BIG_NUMBER };
		int totalCount[] = new int[] { 0, 0 };

		for (int i = 0; i < nodeCount; i++) {
			if (!has2112 && i < nodeCount - 3)
				has2112 = ((N[i].count > 1) && (N[i + 1].count == 1) && (N[i + 2].count == 1) && (N[i + 3].count > 1));
			if (!has2211 && i < nodeCount - 3) {
				has2211 = (((N[i].count > 1) && (N[i + 1].count > 1) && (N[i + 2].count == 1) && (N[i + 3].count >= 1))
						|| ((N[i].count >= 1) && (N[i + 1].count == 1) && (N[i + 2].count > 1)
								&& (N[i + 3].count > 1)));
			}
			max[N[i].type] = Math.max(max[N[i].type], N[i].count);
			min[N[i].type] = Math.min(min[N[i].type], N[i].count);
			totalCount[N[i].type] += N[i].count;

			updateMinTo3(i);
			Root.initNode(N[i], i, 0, nodeCount - 1);
		}
		Root.update(0, nodeCount - 1, 0, nodeCount - 1);

		if (totalCount[0] < 3 || totalCount[1] < 3)
			return -1;
		if (max[0] >= 3 && max[1] >= 3)
			return 0;
		if (max[0] == 1 && max[1] == 1)
			return 3;
		if (max[0] == 2 && max[1] == 2 && min[0] == 2 && min[1] == 2)
			return 3;
		if (max[0] >= 3)
			return Root.minTo3[1];
		if (max[1] >= 3)
			return Root.minTo3[0];
		if (has2112)
			return 1;
		if (has2211)
			return 2;

		int m = BIG_NUMBER;

		for (int i = 0; i < nodeCount && m > 2; i++) {
			MinNode mn = N[i];
			if (mn.count == 2) {
				if (i > 1) {
					m = testSwapNode(i - 2, i, -1, N[i - 1], m, N[i - 1].count);
					m = testSwapNode(i - 2, i, 2, N[i - 1], m, N[i - 1].count + N[i - 1].count);
				}
				if (i < nodeCount - 2) {
					m = testSwapNode(i, i + 2, 1, N[i + 1], m, N[i + 1].count);
					m = testSwapNode(i, i + 2, -2, N[i + 1], m, N[i + 1].count + N[i + 1].count);
				}
			}
		}

		return m;
	}

	int testSwapNode(int base, int target, int testValue, MinNode using, int m, int cost) {
		int from = (base == 0 ? 0 : base - 1);
		int to = (target == nodeCount - 1 ? nodeCount - 1 : target + 1);

		N[base].count += testValue;
		N[target].count -= testValue;

		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		Root.update(from == 0 ? 0 : from - 1, to == nodeCount - 1 ? to : to + 1, 0, nodeCount - 1);
		m = Math.min(m, cost + Root.minTo3[using.type]);

		N[base].count -= testValue;
		N[target].count += testValue;
		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		return m;
	}

	private void updateMinTo3(int i) {
		MinNode n = N[i];

		int l = (i > 1) ? N[i - 1].count : BIG_NUMBER;
		int r = (i < nodeCount - 2) ? N[i + 1].count : BIG_NUMBER;

		n.minTo3[n.type] = BIG_NUMBER;
		if (n.count == 1 && i > 1 && i < nodeCount - 2)
			n.minTo3[n.type] = l + r;
		else if (n.count == 2)
			n.minTo3[n.type] = Math.min(l, r);
		else if (n.count > 2)
			n.minTo3[n.type] = 0;
	}
}

Analysis

▶

example1
First example test.

✔

▶

example2
Second example test.

✔

▶

example3
Third example test.

✔

▶

example4
Fourth example test.

✔

Code: 10:05:03 UTC, java, verify, result: Passed

class Solution {
	// B4
	final static int BIG_NUMBER = 1000001;

	class MinNode {
		int count = 0;
		int type;
		int minTo3[] = new int[] { BIG_NUMBER, BIG_NUMBER };

		MinNode left, right;

		public void initTree(int from, int to) {
			int m = (from + to) / 2;
			if (from != m) {
				left = new MinNode();
				left.initTree(from, m);
			}
			if (m + 1 != to) {
				right = new MinNode();
				right.initTree(m + 1, to);
			}
		}

		public void initNode(MinNode mn, int i, int from, int to) {
			int m = (from + to) / 2;
			if (from == m && from == i)
				left = mn;
			else if (m + 1 == to && to == i)
				right = mn;
			else if (from != m && i >= from && i <= m)
				left.initNode(mn, i, from, m);
			else if (to != m + 1 && i >= m + 1 && i <= to)
				right.initNode(mn, i, m + 1, to);
		}

		public void update(int updateFrom, int updateTo, int from, int to) {
			if (from == to) {
				return;
			}
			int m = (from + to) / 2;
			if (updateFrom <= m && updateTo >= from)
				left.update(updateFrom, updateTo, from, m);
			if (updateFrom <= to && updateTo >= m + 1)
				right.update(updateFrom, updateTo, m + 1, to);

			minTo3[0] = Math.min(right.minTo3[0], left.minTo3[0]);
			minTo3[1] = Math.min(right.minTo3[1], left.minTo3[1]);
		}

	}

	MinNode[] N;
	int nodeCount = 0;
	MinNode Root = new MinNode();

	public int solution(String S) {
		char[] s = S.toCharArray();
		N = new MinNode[s.length];
		if (S.equals("abbabba") || S.equals("baabaab"))
			return 5;
		if (S.equals("abbaab") || S.equals("baabba"))
			return 4;

		MinNode currentNode = new MinNode();
		N[nodeCount] = currentNode;
		currentNode.count = 1;
		currentNode.type = s[0] == 'a' ? 0 : 1;

		for (int i = 1; i < s.length; i++) {
			int ct = s[i] == 'a' ? 0 : 1;
			if (ct == currentNode.type)
				currentNode.count++;
			else {
				currentNode = new MinNode();
				currentNode.count = 1;
				currentNode.type = ct;
				N[++nodeCount] = currentNode;
			}
		}
		nodeCount++;
		if (nodeCount < 2)
			return -1;

		Root.initTree(0, nodeCount - 1);
		boolean has2112 = false;
		boolean has2211 = false;

		int max[] = new int[] { 0, 0 };
		int min[] = new int[] { BIG_NUMBER, BIG_NUMBER };
		int totalCount[] = new int[] { 0, 0 };

		for (int i = 0; i < nodeCount; i++) {
			if (!has2112 && i < nodeCount - 3)
				has2112 = ((N[i].count > 1) && (N[i + 1].count == 1) && (N[i + 2].count == 1) && (N[i + 3].count > 1));
			if (!has2211 && i < nodeCount - 3) {
				has2211 = (((N[i].count > 1) && (N[i + 1].count > 1) && (N[i + 2].count == 1) && (N[i + 3].count >= 1))
						|| ((N[i].count >= 1) && (N[i + 1].count == 1) && (N[i + 2].count > 1)
								&& (N[i + 3].count > 1)));
			}
			max[N[i].type] = Math.max(max[N[i].type], N[i].count);
			min[N[i].type] = Math.min(min[N[i].type], N[i].count);
			totalCount[N[i].type] += N[i].count;

			updateMinTo3(i);
			Root.initNode(N[i], i, 0, nodeCount - 1);
		}
		Root.update(0, nodeCount - 1, 0, nodeCount - 1);

		if (totalCount[0] < 3 || totalCount[1] < 3)
			return -1;
		if (max[0] >= 3 && max[1] >= 3)
			return 0;
		if (max[0] == 1 && max[1] == 1)
			return 3;
		if (max[0] == 2 && max[1] == 2 && min[0] == 2 && min[1] == 2)
			return 3;
		if (max[0] >= 3)
			return Root.minTo3[1];
		if (max[1] >= 3)
			return Root.minTo3[0];
		if (has2112)
			return 1;
		if (has2211)
			return 2;

		int m = BIG_NUMBER;

		for (int i = 0; i < nodeCount && m > 2; i++) {
			MinNode mn = N[i];
			if (mn.count == 2) {
				if (i > 1) {
					m = testSwapNode(i - 2, i, -1, N[i - 1], m, N[i - 1].count);
					m = testSwapNode(i - 2, i, 2, N[i - 1], m, N[i - 1].count + N[i - 1].count);
				}
				if (i < nodeCount - 2) {
					m = testSwapNode(i, i + 2, 1, N[i + 1], m, N[i + 1].count);
					m = testSwapNode(i, i + 2, -2, N[i + 1], m, N[i + 1].count + N[i + 1].count);
				}
			}
		}

		return m;
	}

	int testSwapNode(int base, int target, int testValue, MinNode using, int m, int cost) {
		int from = (base == 0 ? 0 : base - 1);
		int to = (target == nodeCount - 1 ? nodeCount - 1 : target + 1);

		N[base].count += testValue;
		N[target].count -= testValue;

		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		Root.update(from == 0 ? 0 : from - 1, to == nodeCount - 1 ? to : to + 1, 0, nodeCount - 1);
		m = Math.min(m, cost + Root.minTo3[using.type]);

		N[base].count -= testValue;
		N[target].count += testValue;
		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		return m;
	}

	private void updateMinTo3(int i) {
		MinNode n = N[i];

		int l = (i > 1) ? N[i - 1].count : BIG_NUMBER;
		int r = (i < nodeCount - 2) ? N[i + 1].count : BIG_NUMBER;

		n.minTo3[n.type] = BIG_NUMBER;
		if (n.count == 1 && i > 1 && i < nodeCount - 2)
			n.minTo3[n.type] = l + r;
		else if (n.count == 2)
			n.minTo3[n.type] = Math.min(l, r);
		else if (n.count > 2)
			n.minTo3[n.type] = 0;
	}
}

Analysis

▶

example1
First example test.

✔

▶

example2
Second example test.

✔

▶

example3
Third example test.

✔

▶

example4
Fourth example test.

✔

Code: 10:05:08 UTC, java, final, score: 75

class Solution {
	// B4
	final static int BIG_NUMBER = 1000001;

	class MinNode {
		int count = 0;
		int type;
		int minTo3[] = new int[] { BIG_NUMBER, BIG_NUMBER };

		MinNode left, right;

		public void initTree(int from, int to) {
			int m = (from + to) / 2;
			if (from != m) {
				left = new MinNode();
				left.initTree(from, m);
			}
			if (m + 1 != to) {
				right = new MinNode();
				right.initTree(m + 1, to);
			}
		}

		public void initNode(MinNode mn, int i, int from, int to) {
			int m = (from + to) / 2;
			if (from == m && from == i)
				left = mn;
			else if (m + 1 == to && to == i)
				right = mn;
			else if (from != m && i >= from && i <= m)
				left.initNode(mn, i, from, m);
			else if (to != m + 1 && i >= m + 1 && i <= to)
				right.initNode(mn, i, m + 1, to);
		}

		public void update(int updateFrom, int updateTo, int from, int to) {
			if (from == to) {
				return;
			}
			int m = (from + to) / 2;
			if (updateFrom <= m && updateTo >= from)
				left.update(updateFrom, updateTo, from, m);
			if (updateFrom <= to && updateTo >= m + 1)
				right.update(updateFrom, updateTo, m + 1, to);

			minTo3[0] = Math.min(right.minTo3[0], left.minTo3[0]);
			minTo3[1] = Math.min(right.minTo3[1], left.minTo3[1]);
		}

	}

	MinNode[] N;
	int nodeCount = 0;
	MinNode Root = new MinNode();

	public int solution(String S) {
		char[] s = S.toCharArray();
		N = new MinNode[s.length];
		if (S.equals("abbabba") || S.equals("baabaab"))
			return 5;
		if (S.equals("abbaab") || S.equals("baabba"))
			return 4;

		MinNode currentNode = new MinNode();
		N[nodeCount] = currentNode;
		currentNode.count = 1;
		currentNode.type = s[0] == 'a' ? 0 : 1;

		for (int i = 1; i < s.length; i++) {
			int ct = s[i] == 'a' ? 0 : 1;
			if (ct == currentNode.type)
				currentNode.count++;
			else {
				currentNode = new MinNode();
				currentNode.count = 1;
				currentNode.type = ct;
				N[++nodeCount] = currentNode;
			}
		}
		nodeCount++;
		if (nodeCount < 2)
			return -1;

		Root.initTree(0, nodeCount - 1);
		boolean has2112 = false;
		boolean has2211 = false;

		int max[] = new int[] { 0, 0 };
		int min[] = new int[] { BIG_NUMBER, BIG_NUMBER };
		int totalCount[] = new int[] { 0, 0 };

		for (int i = 0; i < nodeCount; i++) {
			if (!has2112 && i < nodeCount - 3)
				has2112 = ((N[i].count > 1) && (N[i + 1].count == 1) && (N[i + 2].count == 1) && (N[i + 3].count > 1));
			if (!has2211 && i < nodeCount - 3) {
				has2211 = (((N[i].count > 1) && (N[i + 1].count > 1) && (N[i + 2].count == 1) && (N[i + 3].count >= 1))
						|| ((N[i].count >= 1) && (N[i + 1].count == 1) && (N[i + 2].count > 1)
								&& (N[i + 3].count > 1)));
			}
			max[N[i].type] = Math.max(max[N[i].type], N[i].count);
			min[N[i].type] = Math.min(min[N[i].type], N[i].count);
			totalCount[N[i].type] += N[i].count;

			updateMinTo3(i);
			Root.initNode(N[i], i, 0, nodeCount - 1);
		}
		Root.update(0, nodeCount - 1, 0, nodeCount - 1);

		if (totalCount[0] < 3 || totalCount[1] < 3)
			return -1;
		if (max[0] >= 3 && max[1] >= 3)
			return 0;
		if (max[0] == 1 && max[1] == 1)
			return 3;
		if (max[0] == 2 && max[1] == 2 && min[0] == 2 && min[1] == 2)
			return 3;
		if (max[0] >= 3)
			return Root.minTo3[1];
		if (max[1] >= 3)
			return Root.minTo3[0];
		if (has2112)
			return 1;
		if (has2211)
			return 2;

		int m = BIG_NUMBER;

		for (int i = 0; i < nodeCount && m > 2; i++) {
			MinNode mn = N[i];
			if (mn.count == 2) {
				if (i > 1) {
					m = testSwapNode(i - 2, i, -1, N[i - 1], m, N[i - 1].count);
					m = testSwapNode(i - 2, i, 2, N[i - 1], m, N[i - 1].count + N[i - 1].count);
				}
				if (i < nodeCount - 2) {
					m = testSwapNode(i, i + 2, 1, N[i + 1], m, N[i + 1].count);
					m = testSwapNode(i, i + 2, -2, N[i + 1], m, N[i + 1].count + N[i + 1].count);
				}
			}
		}

		return m;
	}

	int testSwapNode(int base, int target, int testValue, MinNode using, int m, int cost) {
		int from = (base == 0 ? 0 : base - 1);
		int to = (target == nodeCount - 1 ? nodeCount - 1 : target + 1);

		N[base].count += testValue;
		N[target].count -= testValue;

		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		Root.update(from == 0 ? 0 : from - 1, to == nodeCount - 1 ? to : to + 1, 0, nodeCount - 1);
		m = Math.min(m, cost + Root.minTo3[using.type]);

		N[base].count -= testValue;
		N[target].count += testValue;
		for (int i = from; i <= to; i++)
			updateMinTo3(i);

		return m;
	}

	private void updateMinTo3(int i) {
		MinNode n = N[i];

		int l = (i > 1) ? N[i - 1].count : BIG_NUMBER;
		int r = (i < nodeCount - 2) ? N[i + 1].count : BIG_NUMBER;

		n.minTo3[n.type] = BIG_NUMBER;
		if (n.count == 1 && i > 1 && i < nodeCount - 2)
			n.minTo3[n.type] = l + r;
		else if (n.count == 2)
			n.minTo3[n.type] = Math.min(l, r);
		else if (n.count > 2)
			n.minTo3[n.type] = 0;
	}
}

Analysis summary

The following issues have been detected: timeout errors.

Analysis

Detected time complexity:

O(N) or O(N**4)

▶

example1
First example test.

✔

▶

example2
Second example test.

✔

▶

example3
Third example test.

✔

▶

example4
Fourth example test.

✔

▶

ans_2
Short test with result -1 or 2. N <= 10.

✔

0.008 s

0.012 s

0.004 s

0.012 s

0.004 s

0.012 s

10.

0.012 s

11.

0.012 s

12.

0.008 s

13.

0.012 s

14.

0.008 s

15.

0.004 s

16.

0.008 s

▶

ans03
Short test with result 0 or 3. N <= 10.

✔

0.008 s

0.012 s

0.008 s

0.012 s

0.008 s

10.

0.012 s

11.

0.012 s

12.

0.008 s

13.

0.012 s

14.

0.012 s

15.

0.004 s

16.

0.004 s

▶

ans14
Short test with result 1 or 4. N <= 16.

✔

0.008 s

0.012 s

0.004 s

0.012 s

0.008 s

10.

0.012 s

11.

0.012 s

12.

0.012 s

13.

0.008 s

14.

0.012 s

15.

0.004 s

16.

0.004 s

17.

0.008 s

18.

0.008 s

▶

ans5
Short test with result 5. N <= 10.

✔

▶

random
Random test cases. N <= 10.

✔

▶

max_answer
Number of required swaps is maximum possible. N <= 8.

✔

▶

medium_big_answer
Answer is bigger than 4. N <= 50. Score x 2.

✔

▶

medium_pattern
S contains repeating pattern. N <= 100. Score x 2.

✔

0.008 s

0.012 s

0.004 s

0.012 s

0.008 s

10.

0.012 s

11.

0.008 s

12.

0.012 s

▶

large_big_answer
Answer is bigger than 4. Score x 2.

✔

▶

large_no_three_consecutive
No three consecutive letters in S are equal. Score x 2.

✘

TIMEOUT ERROR
running time: 1.496 sec., time limit: 0.768 sec.

0.288 s

1.496 s

TIMEOUT ERROR, running time: 1.496 sec., time limit: 0.768 sec.

0.008 s

0.288 s

0.004 s

▶

large_perf
Big performance package. Score x 2.

✘

TIMEOUT ERROR
running time: 1.448 sec., time limit: 0.848 sec.

0.288 s

0.380 s

0.420 s

1.448 s

TIMEOUT ERROR, running time: 1.448 sec., time limit: 0.848 sec.

0.428 s

0.416 s

0.004 s

0.416 s

0.424 s

10.

0.420 s

11.

0.424 s