Codeforces Round 892 (Div. 2) C. Another Permutation Problem 纯数学方法 思维题

Codeforces Round 892 (Div. 2) C. Another Permutation Problem

源码：

#include <iostream>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <vector>
#include <stack>
#include <cstdio>
#include <cstring>
#include <cstdlib>
using namespace std;
const int maxn = 550;
long long s[maxn];

int main(){
	int t;
	cin >> t;
	while(t--){
		long long n;
		cin >> n;
		long long ans = 0;
		s[0] = 0;
		for(long long i = 1;i <= n;i++){
			s[i] = s[i-1]+i*i;
		}
		for(long long i = 1;i <= n;i++){
			long long sum = s[i-1];
			long long maxl = 0;
			long long temp;
			for(long long j = i;j <= n;j++){
				temp = (n-(j-i))*j;
				sum += temp;
				if(temp>maxl){
					maxl = temp;
				}
			}
			sum -= maxl;
			if(sum>ans){
				ans = sum;
			}
		}
		cout << ans << endl;
	}
	return 0;
}