Tasks Details
easy
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] = 3We 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] = 3the 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].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used JavaScript
Time spent on task 15 minutes
Notes
not defined yet
Task timeline
Code: 16:12:49 UTC,
java,
autosave
Code: 16:27:20 UTC,
js,
autosave
// 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)
let sum = 0;
let firstPartSum = 0;
let minDifference = Number.MAX_VALUE;
for (let index = 0; index < A.length; index++) {
sum += A[index];
}
for (let index = 0; index < A.length - 1; index++) {
firstPartSum += A[index];
const difference = Math.abs(2 * firstPartSum - sum);
if (difference < minDifference) {
minDifference = difference;
}
}
return minDifference;
}
Code: 16:27:23 UTC,
js,
verify,
result: Passed
// 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)
let sum = 0;
let firstPartSum = 0;
let minDifference = Number.MAX_VALUE;
for (let index = 0; index < A.length; index++) {
sum += A[index];
}
for (let index = 0; index < A.length - 1; index++) {
firstPartSum += A[index];
const difference = Math.abs(2 * firstPartSum - sum);
if (difference < minDifference) {
minDifference = difference;
}
}
return minDifference;
}
Analysis
Code: 16:27:29 UTC,
js,
verify,
result: Passed
// 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)
let sum = 0;
let firstPartSum = 0;
let minDifference = Number.MAX_VALUE;
for (let index = 0; index < A.length; index++) {
sum += A[index];
}
for (let index = 0; index < A.length - 1; index++) {
firstPartSum += A[index];
const difference = Math.abs(2 * firstPartSum - sum);
if (difference < minDifference) {
minDifference = difference;
}
}
return minDifference;
}
Analysis
Code: 16:27:31 UTC,
js,
final,
score:
100
// 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)
let sum = 0;
let firstPartSum = 0;
let minDifference = Number.MAX_VALUE;
for (let index = 0; index < A.length; index++) {
sum += A[index];
}
for (let index = 0; index < A.length - 1; index++) {
firstPartSum += A[index];
const difference = Math.abs(2 * firstPartSum - sum);
if (difference < minDifference) {
minDifference = difference;
}
}
return minDifference;
}Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N)
expand all
Correctness tests
1.
0.072 s
OK
2.
0.072 s
OK
3.
0.072 s
OK
1.
0.072 s
OK
2.
0.072 s
OK
1.
0.072 s
OK
2.
0.072 s
OK
1.
0.072 s
OK
2.
0.072 s
OK
3.
0.072 s
OK
4.
0.072 s
OK
1.
0.072 s
OK
1.
0.072 s
OK
1.
0.072 s
OK
expand all
Performance tests
1.
0.084 s
OK
1.
0.084 s
OK
1.
0.104 s
OK
2.
0.104 s
OK
1.
0.112 s
OK
2.
0.112 s
OK
1.
0.100 s
OK
1.
0.116 s
OK
2.
0.112 s
OK
3.
0.108 s
OK