Test results - Codility

Tasks Details

medium

1. MaxDoubleSliceSum

Find the maximal sum of any double slice.

Task Score

100%

Correctness

100%

Performance

100%

A non-empty array A consisting of N integers is given.

A triplet (X, Y, Z), such that 0 ≤ X < Y < Z < N, is called a double slice.

The sum of double slice (X, Y, Z) is the total of A[X + 1] + A[X + 2] + ... + A[Y − 1] + A[Y + 1] + A[Y + 2] + ... + A[Z − 1].

For example, array A such that:

A[0] = 3 A[1] = 2 A[2] = 6 A[3] = -1 A[4] = 4 A[5] = 5 A[6] = -1 A[7] = 2

contains the following example double slices:

double slice (0, 3, 6), sum is 2 + 6 + 4 + 5 = 17,

double slice (0, 3, 7), sum is 2 + 6 + 4 + 5 − 1 = 16,

double slice (3, 4, 5), sum is 0.

The goal is to find the maximal sum of any double slice.

Write a function:

function solution(A);

that, given a non-empty array A consisting of N integers, returns the maximal sum of any double slice.

For example, given:

A[0] = 3 A[1] = 2 A[2] = 6 A[3] = -1 A[4] = 4 A[5] = 5 A[6] = -1 A[7] = 2

the function should return 17, because no double slice of array A has a sum of greater than 17.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [3..100,000];

each element of array A is an integer within the range [−10,000..10,000].

Solution

Programming language used JavaScript

Time spent on task 35 minutes

Notes

not defined yet

Code: 16:34:34 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(int[] A) {
        // write your code in Java SE 8
    }
}

Code: 16:34:39 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)
}

Code: 17:03:12 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    
}

Code: 17:03:30 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [];
    const right = [];
}

Code: 17:03:59 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [];
    const right = [];

    for (let i = 0; i < N; i++) {
        left.push(Math.max())
    }
}

Code: 17:04:09 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 0; i < N; i++) {
        left.push(Math.max())
    }
}

Code: 17:04:43 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N; i++) {
        left.push(Math.max())
    }
}

Code: 17:04:53 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left.push(Math.max())
    }
}

Code: 17:05:24 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A)
    }
}

Code: 17:05:47 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, )
    }
}

Code: 17:05:57 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, )
    }
}

Code: 17:06:14 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N- ])
    }
}

Code: 17:06:38 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    
}

Code: 17:07:09 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, )
    }
}

Code: 17:07:27 UTC, js, verify, result: Failed

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    return maxDoubleSlice;
}

Analysis

expand all Example tests

▶

example
example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.072 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Invalid result type, integer expected, non-integer number found

Code: 17:07:42 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    return maxDoubleSlice;
}

Code: 17:07:53 UTC, js, verify, result: Failed

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = [0];

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    console.log(left);
    console.log(right)

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    console.log(maxDoubleSlice)

    return maxDoubleSlice;
}

Analysis

expand all Example tests

▶

example
example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.072 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Invalid result type, integer expected, non-integer number found

stdout:

[ 0, 2, 8, 7, 11, 16, 15 ]
[ 0, NaN, NaN, NaN, NaN, NaN, NaN ]
NaN

Code: 17:08:33 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = e;

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    console.log(left);
    console.log(right)

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    console.log(maxDoubleSlice)

    return maxDoubleSlice;
}

Code: 17:08:44 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = [0];
    const right = new Array(N).fill(0);

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    console.log(left);
    console.log(right)

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    console.log(maxDoubleSlice)

    return maxDoubleSlice;
}

Code: 17:08:46 UTC, js, verify, result: Passed

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = new Array(N).fill(0);
    const right = new Array(N).fill(0);

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    console.log(left);
    console.log(right)

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    console.log(maxDoubleSlice)

    return maxDoubleSlice;
}

Analysis

expand all Example tests

▶

example
example test

✔

0.080 s

stdout:

[ 0, 2, 8, 7, 11, 16, 15, 0 ]
[ 0, 16, 14, 8, 9, 5, 0, 0 ]
17

Code: 17:08:54 UTC, js, verify, result: Passed

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = new Array(N).fill(0);
    const right = new Array(N).fill(0);

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    return maxDoubleSlice;
}

Analysis

expand all Example tests

▶

example
example test

✔

0.072 s

Code: 17:08:58 UTC, js, verify, result: Passed

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = new Array(N).fill(0);
    const right = new Array(N).fill(0);

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    return maxDoubleSlice;
}

Analysis

expand all Example tests

▶

example
example test

✔

0.068 s

Code: 17:09:01 UTC, js, final, score: 100

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const N = A.length;
    const left = new Array(N).fill(0);
    const right = new Array(N).fill(0);

    for (let i = 1; i < N - 1; i++) {
        left[i] = Math.max(0, left[i - 1] + A[i]);
        right[N - 1 - i] = Math.max(0, right[N - i] + A[N - 1 - i]);
    }

    let maxDoubleSlice = 0;

    for (let i = 1; i < N - 1; i++) {
        maxDoubleSlice = Math.max(maxDoubleSlice, left[i - 1] + right[i + 1]);
    }

    return maxDoubleSlice;
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example
example test

✔

0.072 s

expand all Correctness tests

▶

simple1
first simple test

✔

0.072 s

0.068 s

▶

simple2
second simple test

✔

0.072 s

▶

simple3
third simple test

✔

0.072 s

▶

negative
all negative numbers

✔

0.072 s

▶

positive
all positive numbers

✔

0.072 s

▶

extreme_triplet
three elements

✔

0.072 s

expand all Performance tests

▶

small_random1
random, numbers form -10**4 to 10**4, length = 70

✔

0.072 s

▶

small_random2
random, numbers from -30 to 30, length = 300

✔

0.072 s

▶

medium_range
-1000, ..., 1000

✔

0.072 s

▶

large_ones
random numbers from -1 to 1, length = ~100,000

✔

0.116 s

▶

large_random
random, length = ~100,000

✔

0.124 s

▶

extreme_maximal
all maximal values, length = ~100,000

✔

0.124 s

▶

large_sequence
many the same small sequences, length = ~100,000

✔

0.116 s

0.120 s