Test results - Codility

Tasks Details

easy

1. MaxSliceSum

Find a maximum sum of a compact subsequence of array elements.

Task Score

69%

Correctness

75%

Performance

60%

A non-empty array A consisting of N integers is given. A pair of integers (P, Q), such that 0 ≤ P ≤ Q < N, is called a slice of array A. The sum of a slice (P, Q) is the total of A[P] + A[P+1] + ... + A[Q].

Write a function:

class Solution { public int solution(int[] A); }

that, given an array A consisting of N integers, returns the maximum sum of any slice of A.

For example, given array A such that:

A[0] = 3 A[1] = 2 A[2] = -6 A[3] = 4 A[4] = 0

the function should return 5 because:

(3, 4) is a slice of A that has sum 4,

(2, 2) is a slice of A that has sum −6,

(0, 1) is a slice of A that has sum 5,

no other slice of A has sum greater than (0, 1).

Write an efficient algorithm for the following assumptions:

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

each element of array A is an integer within the range [−1,000,000..1,000,000];

the result will be an integer within the range [−2,147,483,648..2,147,483,647].

Solution

Programming language used Java 21

Time spent on task 54 minutes

Notes

not defined yet

Code: 07:48:37 UTC, java, autosave

show code in pop-up

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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(int[] A) {
        // write your code in Java SE 8
    }
}

Code: 08:41:39 UTC, java, autosave

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 49 50 51 52 53 54 55

// 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(int[] A) {
        // write your code in Java SE 8
        // 배열의 요소 확인 (모두 음수 or 모두 양수 or 음수/양수 혼합 인지 여부)
        boolean isAllMinus = true;
        boolean isAllPlus = true;

        for (int n : A) {
            if (n > 0) {
                isAllMinus = false;
            }
            if (n < 0) {
                isAllPlus = false;
            }
        }

        int nMax = Integer.MIN_VALUE;

        // 모두 음수인 경우 -> 가장 큰 값 리턴
        if (isAllMinus) {
            for (int n : A) {
                nMax = Math.max(n, nMax);
            }
            return nMax;
        }

        // 모두 양수인 경우 -> 모든 값 합하여 리턴
        if (isAllPlus) {
            return IntStream.of(A).sum();
        }

        // 음수와 양수가 섞인 경우 -> 음수를 기준으로 slice한 후 각각의 합 중 최대값 리턴
        TreeSet<Integer> tSet = new TreeSet<>();
        int sliceSum = 0;
        for (int i=0; i<A.length; i++) {
            if (A[i] >= 0) {
                sliceSum += A[i];
            } else {
                tSet.add(sliceSum);
                sliceSum = 0;
            }
            if (i == A.length-1) {
                tSet.add(sliceSum);
            }
        }
        //System.out.println(tSet);
        return tSet.last();
    }
}

Code: 08:41:49 UTC, java, autosave

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 49 50 51 52 53 54 55 56

// you can also use imports, for example:
// import java.util.*;
import java.util.TreeSet;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        // 배열의 요소 확인 (모두 음수 or 모두 양수 or 음수/양수 혼합 인지 여부)
        boolean isAllMinus = true;
        boolean isAllPlus = true;

        for (int n : A) {
            if (n > 0) {
                isAllMinus = false;
            }
            if (n < 0) {
                isAllPlus = false;
            }
        }

        int nMax = Integer.MIN_VALUE;

        // 모두 음수인 경우 -> 가장 큰 값 리턴
        if (isAllMinus) {
            for (int n : A) {
                nMax = Math.max(n, nMax);
            }
            return nMax;
        }

        // 모두 양수인 경우 -> 모든 값 합하여 리턴
        if (isAllPlus) {
            return IntStream.of(A).sum();
        }

        // 음수와 양수가 섞인 경우 -> 음수를 기준으로 slice한 후 각각의 합 중 최대값 리턴
        TreeSet<Integer> tSet = new TreeSet<>();
        int sliceSum = 0;
        for (int i=0; i<A.length; i++) {
            if (A[i] >= 0) {
                sliceSum += A[i];
            } else {
                tSet.add(sliceSum);
                sliceSum = 0;
            }
            if (i == A.length-1) {
                tSet.add(sliceSum);
            }
        }
        //System.out.println(tSet);
        return tSet.last();
    }
}

Code: 08:41:52 UTC, java, verify, result: Passed

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 49 50 51 52 53 54 55 56

// you can also use imports, for example:
// import java.util.*;
import java.util.TreeSet;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        // 배열의 요소 확인 (모두 음수 or 모두 양수 or 음수/양수 혼합 인지 여부)
        boolean isAllMinus = true;
        boolean isAllPlus = true;

        for (int n : A) {
            if (n > 0) {
                isAllMinus = false;
            }
            if (n < 0) {
                isAllPlus = false;
            }
        }

        int nMax = Integer.MIN_VALUE;

        // 모두 음수인 경우 -> 가장 큰 값 리턴
        if (isAllMinus) {
            for (int n : A) {
                nMax = Math.max(n, nMax);
            }
            return nMax;
        }

        // 모두 양수인 경우 -> 모든 값 합하여 리턴
        if (isAllPlus) {
            return IntStream.of(A).sum();
        }

        // 음수와 양수가 섞인 경우 -> 음수를 기준으로 slice한 후 각각의 합 중 최대값 리턴
        TreeSet<Integer> tSet = new TreeSet<>();
        int sliceSum = 0;
        for (int i=0; i<A.length; i++) {
            if (A[i] >= 0) {
                sliceSum += A[i];
            } else {
                tSet.add(sliceSum);
                sliceSum = 0;
            }
            if (i == A.length-1) {
                tSet.add(sliceSum);
            }
        }
        //System.out.println(tSet);
        return tSet.last();
    }
}

Analysis

expand all Example tests

▶

example

✔

0.004 s

Code: 08:41:56 UTC, java, final, score: 69

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 49 50 51 52 53 54 55 56

// you can also use imports, for example:
// import java.util.*;
import java.util.TreeSet;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        // 배열의 요소 확인 (모두 음수 or 모두 양수 or 음수/양수 혼합 인지 여부)
        boolean isAllMinus = true;
        boolean isAllPlus = true;

        for (int n : A) {
            if (n > 0) {
                isAllMinus = false;
            }
            if (n < 0) {
                isAllPlus = false;
            }
        }

        int nMax = Integer.MIN_VALUE;

        // 모두 음수인 경우 -> 가장 큰 값 리턴
        if (isAllMinus) {
            for (int n : A) {
                nMax = Math.max(n, nMax);
            }
            return nMax;
        }

        // 모두 양수인 경우 -> 모든 값 합하여 리턴
        if (isAllPlus) {
            return IntStream.of(A).sum();
        }

        // 음수와 양수가 섞인 경우 -> 음수를 기준으로 slice한 후 각각의 합 중 최대값 리턴
        TreeSet<Integer> tSet = new TreeSet<>();
        int sliceSum = 0;
        for (int i=0; i<A.length; i++) {
            if (A[i] >= 0) {
                sliceSum += A[i];
            } else {
                tSet.add(sliceSum);
                sliceSum = 0;
            }
            if (i == A.length-1) {
                tSet.add(sliceSum);
            }
        }
        //System.out.println(tSet);
        return tSet.last();
    }
}

Analysis summary

The following issues have been detected: wrong answers.

For example, for the input [3, -2, 3] the solution returned a wrong answer (got 3 expected 4).

Analysis

expand all Example tests

▶

example

✔

0.008 s

expand all Correctness tests

▶

one_element

✔

0.004 s

0.088 s

▶

two_elements

✔

0.004 s

0.008 s

0.088 s

0.084 s

0.004 s

0.084 s

0.088 s

▶

three_elements

✘

WRONG ANSWER
got 3 expected 4

0.004 s

0.008 s

0.004 s

0.008 s

0.004 s

10.

0.008 s

11.

0.004 s

12.

0.008 s

13.

0.008 s

14.

0.084 s

15.

0.088 s

16.

0.004 s

17.

0.092 s

18.

0.088 s

19.

0.008 s

20.

0.008 s

21.

0.004 s

WRONG ANSWER, got 3 expected 4

22.

0.008 s

23.

0.088 s

24.

0.088 s

25.

0.008 s

26.

0.088 s

27.

0.088 s

▶

simple

✔

0.008 s

▶

extreme_minimum

✔

0.008 s

▶

fifty_random

✘

WRONG ANSWER
got 1480 expected 2662

0.008 s

WRONG ANSWER, got 1480 expected 2662

▶

neg_const

✔

0.008 s

▶

pos_const

✔

0.088 s

expand all Performance tests

▶

high_low_1Kgarbage

✔

0.008 s

▶

1Kgarbage_high_low

✔

0.008 s

▶

growing_saw

✘

WRONG ANSWER
got 91 expected 252

0.008 s

WRONG ANSWER, got 91 expected 252

▶

blocks

✘

WRONG ANSWER
got 501 expected 1001

0.456 s

WRONG ANSWER, got 501 expected 1001

▶

growing_negative

✔

0.536 s