Que50.java

/**
 * @author: hyl
 * @date: 2019/08/15
 **/
public class Que50 {

    // Parameters:
    //    numbers:     an array of integers
    //    length:      the length of array numbers
    //    duplication: (Output) the duplicated number in the array number,length of duplication array is 1,so using duplication[0] = ? in implementation;
    //                  Here duplication like pointor in C/C++, duplication[0] equal *duplication in C/C++
    //    这里要特别注意~返回任意重复的一个，赋值duplication[0]
    // Return value:       true if the input is valid, and there are some duplications in the array number
    //                     otherwise false
    public boolean duplicate(int numbers[],int length,int [] duplication) {


        if (numbers == null || length == 0){
            return false;
        }

        boolean[] k = new boolean[length];

        for (int i = 0; i < length; i++) {

            if (k[numbers[i]] == true){
                duplication[0] = numbers[i];
                return true;
            }

            k[numbers[i]] = true;
        }
        return false;
    }
}