将数组进行排序，然后比较数组中相邻的俩个数时候相等

public boolean duplicate(int numbers[],int length,int [] duplication) {
            if(numbers==null||length<=1) 
                return false;
        int temp;
        boolean flage = false;
//排序算法
        for(int i=0;i<length-1;i++){
            for(int j=0;j<length-i-1;j++){
                if(numbers[j]<=numbers[j+1]){
               temp = numbers[j];
               numbers[j] = numbers[j+1];
               numbers[j+1] = temp;
           }   }}
//比较相邻的连个是是否相等
        for(int i = 0;i<length-1;i++)
            if(numbers[i]==numbers[i+1]){
                flage= true;
                duplication[0] = numbers[i];
            }
        return flage;
    }