Codility – FrogRiverOne 문제 풀이 (난이도 : 하)

class Solution {
    public int solution(int X, int[] A) {
        // write your code in Java SE 8
        int leafList[] = new int[X+1];
        for(int i = 0 ; i < leafList.length ; i++){
            leafList[i] = -1;   
        }
        
        for(int i = 0 ; i < A.length ; i++){
            int leaf = A[i];
            if(leaf <= X ){
                if(leafList[leaf] == -1){
                    leafList[leaf] = i;
                }
                else{
                    leafList[leaf] = Math.min(i, leafList[leaf]);    
                }
            }
        }
        
        int result = 0;
        for(int i = 1 ; i < leafList.length ; i++){
            if(leafList[i] == -1){
                result = -1;
                break;
            }
            result = Math.max(result, leafList[i]);
        }
        
        return result;
    }
}