public class DumplicatArray {

public static void main(String args[]){

int[] number=new int[0];

int[] fa={0};

duplicate(number,number.length,fa);

System.out.println(fa[0]);

}

// 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 static boolean duplicate(int numbers[],int length,int [] duplication) {

if(numbers.length==0){

return false;

}

int[] num=new int[numbers.length];

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

num[numbers[i]]++;

}

for(int j=0;j<num.length;j++){

if(num[j]>1){

duplication[0]=j;

return true;

}

}

return false;

}

}