[codility] lesson4 - FrogRiverOne

// 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 X, int[] A) {
        // write your code in Java SE 8
        
        int[] positions = new int[X];
        int result = -1;
        int count = 0;
        int i;
        for (i = 0; i < A.length; i++) {
            int idx = A[i] - 1;
            if (idx < X) {
                if ( positions[idx] == 0 ) {
                    positions[idx]++;
                    count++;
                }
            }
            
            if (count == X) {
                result = i;
                break;
            }
        }
        
        return result;
    }
    
}