用搜索，模拟。但你会发现规律。

m可以表示为x的函数!

大家好好想想,这个函数很简单.

是一个经过(0,0)的二次函数!!!

当然，如果我把解析式都帖出来就跟帖答案差不多了。。。

#include <iostream>

using namespace std ;

int n ;

int main()
{
    cin >> n ;
    cout << n * n + 2 * n ;
    return 0 ;
}

666!

#include <iostream>
using namespace std;
int main(int argc, char** argv)
{
long long x,z;
scanf("%lld",&x);
z=2*x*(x+1)-x*x;
printf("%lld",z);
return 0;
}

...

先解了木木版，再过来的，凭着下意识试了三次，改了下木木板的公式，于是……

#include <iostream>
using namespace std ;
int main()
{
    long long x;
cin >>x;
cout <<(x + 1) *(x+1)-1;
return 0;
}

/*
真水题~
式子自己手动推导叭~~
*/
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

long long x;

int main()
{
    cin>>x;
    cout<<x*x+2*x<<endl;
    return 0;
}
     

#include<bits/stdc++.h>
using namespace std;
int main()
{
int a;
cin>>a;
cout<<a*(a+2);
return 0;
}

foo.cpp:3:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
main()
^
测试数据 #0: Accepted, time = 0 ms, mem = 560 KiB, score = 5
测试数据 #1: Accepted, time = 0 ms, mem = 560 KiB, score = 15
测试数据 #2: Accepted, time = 0 ms, mem = 556 KiB, score = 15
测试数据 #3: Accepted, time = 0 ms, mem = 560 KiB, score = 20
测试数据 #4: Accepted, time = 0 ms, mem = 560 KiB, score = 20
测试数据 #5: Accepted, time = 0 ms, mem = 556 KiB, score = 25
Accepted, time = 0 ms, mem = 560 KiB, score = 100
刷RP

RP **1000+ ** 纪念！！！