*寒假水105——Reduced ID Numbers

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本文介绍了一个算法问题，即如何找到使学生ID号在模运算下唯一对应的最小正整数m。通过暴力搜索的方法解决了该问题，并给出了完整的C++实现代码。

T. Chur teaches various groups of students at university U. Every U-student has a unique Student Identification Number (SIN). A SIN s is an integer in the range 0 ≤ s ≤ MaxSIN with MaxSIN = 10 6-1. T. Chur finds this range of SINs too large for identification within her groups. For each group, she wants to find the smallest positive integer m, such that within the group all SINs reduced modulo m are unique.

Input

On the first line of the input is a single positive integer N, telling the number of test cases (groups) to follow. Each case starts with one line containing the integer G (1 ≤ G ≤ 300): the number of students in the group. The following G lines each contain one SIN. The SINs within a group are distinct, though not necessarily sorted.

Output

For each test case, output one line containing the smallest modulus m, such that all SINs reduced modulo m are distinct.

Sample Input

Sample Output

1
8

#include<iostream>
#include<stdio.h>  
#include<memory.h>  

using namespace std;

int stu[302];  
bool bear[1000000];  
int stun,grn,ans;    
  
bool test(int a)  
{  
    int rem,i;  
    memset(bear,0,sizeof(bool)*ans);  
    for(i=0;i<stun;++i)  
    {  
        rem=stu[i]%a;  
        if(bear[rem])  
        {  
            return 0;  
        }  
        else  
        {  
            bear[rem]=1;  
        }  
    }  
    return 1;  
}  
  
int main()  
{  
    cin>>grn;  
    while(grn--)  
    {  
        cin>>stun;  
        for(ans=0;ans<stun;++ans)  
        {  
            cin>>stu[ans];  
        }  
        while(!test(ans))  
        {  
            ++ans;  
        }  
        cout<<ans<<endl;  
    }  
    return 0;  
}

题解：当然是最最最喜欢的暴力搜索啦！