Test results - Codility

Tasks Details

easy

1. Brackets

Determine whether a given string of parentheses (multiple types) is properly nested.

Task Score

100%

Correctness

100%

Performance

100%

A string S consisting of N characters is considered to be properly nested if any of the following conditions is true:

S is empty;

S has the form "(U)" or "[U]" or "{U}" where U is a properly nested string;

S has the form "VW" where V and W are properly nested strings.

For example, the string "{[()()]}" is properly nested but "([)()]" is not.

Write a function:

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

that, given a string S consisting of N characters, returns 1 if S is properly nested and 0 otherwise.

For example, given S = "{[()()]}", the function should return 1 and given S = "([)()]", the function should return 0, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [0..200,000];

string S is made only of the following characters: '(', '{', '[', ']', '}' and/or ')'.

Solution

Programming language used Java 8

Time spent on task 14 minutes

Notes

not defined yet

Task timeline

Code: 11:26:50 UTC, java, autosave

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// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        // write your code in Java SE 8
    }
}

Code: 11:27:25 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12

// you can also use imports, for example:
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Integer> st = new Stack<Integer>();
        // write your code in Java SE 8
    }
}

Code: 11:27:55 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12

// you can also use imports, for example:
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Integer>();
        // write your code in Java SE 8
    }
}

Code: 11:28:05 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12

// you can also use imports, for example:
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();
        
    }
}

Code: 11:28:19 UTC, java, autosave

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// you can also use imports, for example:
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();
        for(int i)
    }
}

Code: 11:37:20 UTC, java, autosave

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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

import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();
        Stack<Character> st1 = new Stack<Character>();
        Stack<Character> st2 = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(') {
                st.push(S.charAt(i));
            } else if (S.charAt(i) == '[') {
                st1.push(S.charAt(i));
            } else if (S.charAt(i) == '{') {
                st2.push(S.charAt(i));
            } else if ( S.charAt(i) == ')'){
                if (st.size() > 0) {
                    st.pop();
                } else {
                    return 0;
                }
            }  else if ( S.charAt(i) == ']'){
                if (st1.size() > 0) {
                    st1.pop();
                } else {
                    return 0;
                }
            } else if ( S.charAt(i) == '}'){
                if (st2.size() > 0) {
                    st2.pop();
                } else {
                    return 0;
                }
            }
        }
        
        if(st.size() > 0 || st1.size() >0 || st2.size()> 0){
            return 0;
        }else{
            return 1;
        }
    }
}

Code: 11:37:20 UTC, java, verify, result: Failed

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import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();
        Stack<Character> st1 = new Stack<Character>();
        Stack<Character> st2 = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(') {
                st.push(S.charAt(i));
            } else if (S.charAt(i) == '[') {
                st1.push(S.charAt(i));
            } else if (S.charAt(i) == '{') {
                st2.push(S.charAt(i));
            } else if ( S.charAt(i) == ')'){
                if (st.size() > 0) {
                    st.pop();
                } else {
                    return 0;
                }
            }  else if ( S.charAt(i) == ']'){
                if (st1.size() > 0) {
                    st1.pop();
                } else {
                    return 0;
                }
            } else if ( S.charAt(i) == '}'){
                if (st2.size() > 0) {
                    st2.pop();
                } else {
                    return 0;
                }
            }
        }
        
        if(st.size() > 0 || st1.size() >0 || st2.size()> 0){
            return 0;
        }else{
            return 1;
        }
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.008 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.008 s

WRONG ANSWER, got 1 expected 0

Code: 11:40:19 UTC, java, autosave

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// you can also use imports, for example:

import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(' || S.charAt(i) == '[' || S.charAt(i) == '{') {
                st.push(S.charAt(i));
            } else if ( S.charAt(i) == ')'){
                if (st.size() > 0) {
                    if(st.pop() != '('){
                        return 0;
                    }
                } else {
                    return 0;
                }
            }  else if ( S.charAt(i) == ']'){
                if (st.size() > 0) {
                    if(st.pop() != '['){
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if ( S.charAt(i) == '}'){
                if (st.size() > 0) {
                    if(st.pop() != '{'){
                        return 0;
                    }
                } else {
                    return 0;
                }
            }
        }

        if(st.size() > 0){
            return 0;
        }else{
            return 1;
        }
    }
}

Code: 11:40:19 UTC, java, verify, result: Passed

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// you can also use imports, for example:

import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(' || S.charAt(i) == '[' || S.charAt(i) == '{') {
                st.push(S.charAt(i));
            } else if ( S.charAt(i) == ')'){
                if (st.size() > 0) {
                    if(st.pop() != '('){
                        return 0;
                    }
                } else {
                    return 0;
                }
            }  else if ( S.charAt(i) == ']'){
                if (st.size() > 0) {
                    if(st.pop() != '['){
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if ( S.charAt(i) == '}'){
                if (st.size() > 0) {
                    if(st.pop() != '{'){
                        return 0;
                    }
                } else {
                    return 0;
                }
            }
        }

        if(st.size() > 0){
            return 0;
        }else{
            return 1;
        }
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.008 s

▶

example2
example test 2

✔

0.008 s

Code: 11:40:28 UTC, java, verify, result: Passed

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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

// you can also use imports, for example:

import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(' || S.charAt(i) == '[' || S.charAt(i) == '{') {
                st.push(S.charAt(i));
            } else if (S.charAt(i) == ')') {
                if (st.size() > 0) {
                    if (st.pop() != '(') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if (S.charAt(i) == ']') {
                if (st.size() > 0) {
                    if (st.pop() != '[') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if (S.charAt(i) == '}') {
                if (st.size() > 0) {
                    if (st.pop() != '{') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            }
        }

        if (st.size() > 0) {
            return 0;
        } else {
            return 1;
        }
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.004 s

▶

example2
example test 2

✔

0.004 s

Code: 11:40:33 UTC, java, final, score: 100

show code in pop-up

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

// you can also use imports, for example:

import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        Stack<Character> st = new Stack<Character>();

        for (int i = 0; i < S.length(); i++) {
            if (S.charAt(i) == '(' || S.charAt(i) == '[' || S.charAt(i) == '{') {
                st.push(S.charAt(i));
            } else if (S.charAt(i) == ')') {
                if (st.size() > 0) {
                    if (st.pop() != '(') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if (S.charAt(i) == ']') {
                if (st.size() > 0) {
                    if (st.pop() != '[') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            } else if (S.charAt(i) == '}') {
                if (st.size() > 0) {
                    if (st.pop() != '{') {
                        return 0;
                    }
                } else {
                    return 0;
                }
            }
        }

        if (st.size() > 0) {
            return 0;
        } else {
            return 1;
        }
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example1
example test 1

✔

0.004 s

▶

example2
example test 2

✔

0.008 s

expand all Correctness tests

▶

negative_match
invalid structures

✔

0.008 s

▶

empty
empty string

✔

0.008 s

▶

simple_grouped
simple grouped positive and negative test, length=22

✔

0.004 s

0.008 s

0.004 s

expand all Performance tests

▶

large1
simple large positive test, 100K ('s followed by 100K )'s + )(

✔

0.280 s

0.008 s

0.028 s

▶

large2
simple large negative test, 10K+1 ('s followed by 10K )'s + )( + ()

✔

0.032 s

0.004 s

▶

large_full_ternary_tree
tree of the form T=(TTT) and depth 11, length=177K+

✔

0.256 s

▶

multiple_full_binary_trees
sequence of full trees of the form T=(TT), depths [1..10..1], with/without some brackets at the end, length=49K+

✔

0.076 s

0.072 s

0.028 s

▶

broad_tree_with_deep_paths
string of the form [TTT...T] of 300 T's, each T being '{{{...}}}' nested 200-fold, length=120K+

✔

0.188 s