King of Karaoke（map）（The 15th Zhejiang Provincial Collegiate Programming Contest Sponsored by TuSimple

题目链接：http://acm.zju.edu.cn/onlinejudge/showContestProblem.do?problemId=5753

题意：输入两个数组a，b，求一个数T使ai+T==bi的数量最多

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <map>

using namespace std;

const int maxn=1e5+20;

int T,n,mx,num;
int a[maxn],b[maxn],c[maxn];
map<int,int>mp;

int main()
{
    ios::sync_with_stdio(false);
    cin>>T;
    while(T--)
    {
        cin>>n;
        mx=0;
        mp.clear();
        for(int i=0;i<n;i++) cin>>a[i];
        for(int i=0;i<n;i++) cin>>b[i];

        for(int i=0;i<n;i++)
        {
            c[i]=a[i]-b[i];
            mp[c[i]]++;
            num++;
        }
        for(int i=0;i<n;i++) mx=max(mx,mp[c[i]]);
        cout<<mx<<endl;



    }
    return 0;
}