[GO] [100%] PermCheck (src & junit)

Painless

PermCheck

Check if array A is a permutation.

Task description

Given a non-empty array A consisting of N integers.

A permutation is a sequence that contains each element from 1 to N only once.

For example, the following array A:

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

Is a permutation, but array A looks like this:

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

Is not a permutation because the value 2 is missing.

The goal is to see if array A is permuted.

Write a function:

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

That is, given array A, it returns 1 if array A is permuted, 0 otherwise.

For example, given the following array A:

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

The function must return 1.

Given the following array A:

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

The function must return 0.

Write an efficient algorithm for the following assumptions:

• N is an integer in the range [1..100,000].
• Each element of array A is an integer in the range [1..1,000,000,000].

solve

Program PermCheckSolution.java

PermCheckSolution.java

    public int solution(int[] A) {
        java.util.Arrays.sort(A);
        for (int i = 0; i < A.length; i++) {
            if (A[i] == i + 1) continue;
            else return 0;
        }

        return 1;
    }

Detected time complexity:
O(N) or O(N * log(N))

jUnit PermCheckSolutionTest.java

Report Candidate Report: trainingVGBR4Z-S47