Tasks Details
easy
Find the missing element in a given permutation.
Task Score
100%
Correctness
100%
Performance
100%
An array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
function solution(A);
that, given an array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2 A[1] = 3 A[2] = 1 A[3] = 5the function should return 4, as it is the missing element.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- the elements of A are all distinct;
- each element of array A is an integer within the range [1..(N + 1)].
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used JavaScript
Time spent on task 5 minutes
Notes
not defined yet
Task timeline
Code: 06:11:32 UTC,
java,
autosave
Code: 06:12:34 UTC,
js,
verify,
result: Passed
Analysis
Code: 06:12:49 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort();
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
Analysis
Code: 06:12:56 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort();
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
Code: 06:13:34 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort();
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
console.log(i, A[i], i+1);
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
Code: 06:13:53 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort();
console.log(A);
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
console.log(i, A[i], i+1);
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
expand all
User tests
1.
0.076 s
OK
function result: 2
function result: 2
stdout:
[ 1, 10, 2, 3, 4, 5, 6, 7, 8 ] 1 10 2
Code: 06:15:33 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort((a,b) => {
return a-b;
});
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
console.log(i, A[i], i+1);
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
Code: 06:15:56 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort((a,b) => {
return a-b;
});
console.log(A);
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
console.log(i, A[i], i+1);
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
expand all
User tests
1.
0.076 s
OK
function result: 9
function result: 9
stdout:
[ 1, 2, 3, 4, 5, 6, 7, 8, 10 ] 8 10 9
Code: 06:16:08 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort((a,b) => {
return a-b;
});
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
Code: 06:16:13 UTC,
js,
verify,
result: Passed
function solution(A) {
A.sort((a,b) => {
return a-b;
});
for(let i=0;i<A.length;i++){
if(A[i] != i+1){
return i+1;
}
}
return A.length + 1;
}
User test case 1:
[1, 2, 3, 4, 5, 6, 7, 8, 10]
Analysis
Code: 06:16:16 UTC,
js,
final,
score:
100
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
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
1.
0.072 s
OK
2.
0.072 s
OK
3.
0.072 s
OK
1.
0.072 s
OK
expand all
Performance tests
1.
0.112 s
OK
1.
0.112 s
OK
1.
0.212 s
OK
2.
0.152 s
OK
3.
0.152 s
OK
1.
0.216 s
OK
1.
0.176 s
OK