数组中重复的数字

package 数组中重复的数字;public class Solution {    // 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) {        for (int i = 0; i < length;i++ ) {            if (i != numbers[i]) {                int m = numbers[i];                if (numbers[m] == m) {                    duplication[0] = m;                    return true;                } else {                    numbers[i] = numbers[m];                    numbers[m] = m;                    i--;                }            }        }        return false;    }    public static void main(String[] args) {        int[] numbers = { 0, 1, 2, 1 };        int[] duplication = new int[1];        System.out.println(new Solution().duplicate(numbers, numbers.length, duplication));    }}