Test results - Codility

Tasks Details

easy

1. TapeEquilibrium

Minimize the value |(A[0] + ... + A[P-1]) - (A[P] + ... + A[N-1])|.

Task Score

100%

Correctness

100%

Performance

100%

A non-empty array A consisting of N integers is given. Array A represents numbers on a tape.

Any integer P, such that 0 < P < N, splits this tape into two non-empty parts: A[0], A[1], ..., A[P − 1] and A[P], A[P + 1], ..., A[N − 1].

The difference between the two parts is the value of: |(A[0] + A[1] + ... + A[P − 1]) − (A[P] + A[P + 1] + ... + A[N − 1])|

In other words, it is the absolute difference between the sum of the first part and the sum of the second part.

For example, consider array A such that:

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

We can split this tape in four places:

P = 1, difference = |3 − 10| = 7

P = 2, difference = |4 − 9| = 5

P = 3, difference = |6 − 7| = 1

P = 4, difference = |10 − 3| = 7

Write a function:

function solution(A);

that, given a non-empty array A of N integers, returns the minimal difference that can be achieved.

For example, given:

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

the function should return 1, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [2..100,000];

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

Solution

Programming language used JavaScript

Time spent on task 7 minutes

Notes

not defined yet

Task timeline

Code: 08:42:05 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: 08:42:10 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: 08:43:03 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: 08:43:34 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) {

    let left = A[0];
    
    for (let i = 1; i < A.length)
}

Code: 08:43:45 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length)
}

Code: 08:43:59 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
}

Code: 08:44:29 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) {

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

}

Code: 08:44:54 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) {

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

}

Code: 08:45:06 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) {

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

}

Code: 08:45:25 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.min(left,right);
    for (let i = 1; i < A.length-1; i++){
        if (min > (left+A[i]) )
    }

}

Code: 08:45:38 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.min(left,right);
    for (let i = 1; i < A.length-1; i++){
        if (min > (Math.min(left+A[i],right-A[i]) )
    }

}

Code: 08:46:06 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = abs()
    for (let i = 1; i < A.length-1; i++){
        if (min > (Math.min(left+A[i],right-A[i]) )
    }

}

Code: 08:46:21 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        if (min > (Math.min(left+A[i],right-A[i]) )
    }

}

Code: 08:46:32 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        if (min > (Math.abs(left+A[i],right-A[i]) )
    }

}

Code: 08:46:55 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left = left + A[i];
        right = right - A[i]
        if (min > (Math.abs(left+A[i],right-A[i]) )
    }

}

Code: 08:47:07 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left+A[i],right-A[i]) )
    }

}

Code: 08:47:18 UTC, js, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

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

function solution(A) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right)) )
    }

}

Code: 08:47:36 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right))) {
            min = Math.abs(left - right));
        }
    }
    return min;

}

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:

solution.js:16
            min = Math.abs(left - right));
                                        ^

SyntaxError: Unexpected token )
    at createScript (vm.js:80:10)
    at Object.runInNewContext (vm.js:135:10)
    at getSolution (/tmp/exec.js:392:29)
    at Promise.resolve.then (/tmp/exec.js:426:34)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:686:11)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

Code: 08:47:46 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) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right))) {
            min = Math.abs(left - right);
        }
    }
    return min;

}

Analysis

expand all Example tests

▶

example
example test

✔

0.116 s

Code: 08:47:52 UTC, js, 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

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

function solution(A) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right))) {
            min = Math.abs(left - right);
        }
    }
    return min;

}

Analysis

expand all Example tests

▶

example
example test

✔

0.068 s

Code: 08:48:35 UTC, js, 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

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

function solution(A) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right))) {
            min = Math.abs(left - right);
        }
    }
    return min;

}

Analysis

expand all Example tests

▶

example
example test

✔

0.072 s

Code: 08:48:38 UTC, js, 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

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

function solution(A) {

    let left = A[0];
    let right = 0;    
    for (let i = 1; i < A.length; i++){
        right += A[i]
    }
    let min = Math.abs(left - right);
    for (let i = 1; i < A.length-1; i++){
        left += A[i];
        right -= A[i];
        if (min > (Math.abs(left - right))) {
            min = Math.abs(left - right);
        }
    }
    return min;

}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example
example test

✔

0.068 s

expand all Correctness tests

▶

double
two elements

✔

0.068 s

▶

simple_positive
simple test with positive numbers, length = 5

✔

0.068 s

▶

simple_negative
simple test with negative numbers, length = 5

✔

0.072 s

0.068 s

▶

simple_boundary
only one element on one of the sides

✔

0.072 s

0.068 s

▶

small_random
random small, length = 100

✔

0.068 s

▶

small_range
range sequence, length = ~1,000

✔

0.072 s

▶

small
small elements

✔

0.072 s

expand all Performance tests

▶

medium_random1
random medium, numbers from 0 to 100, length = ~10,000

✔

0.084 s

▶

medium_random2
random medium, numbers from -1,000 to 50, length = ~10,000

✔

0.084 s

▶

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

✔

0.104 s

▶

large_random
random large, length = ~100,000

✔

0.112 s

▶

large_sequence
large sequence, length = ~100,000

✔

0.096 s

▶

large_extreme
large test with maximal and minimal values, length = ~100,000

✔

0.108 s

0.112 s

0.108 s