LA 7359 Sum Kind Of Problem （数学，水题）

题意：给定一个n，求前 n 个正整数，正奇数，正偶数之和。

析：没什么好说的，用前 n 项和公式即可。

代码如下：

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
#include <stack>
using namespace std;

typedef long long LL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const double inf = 0x3f3f3f3f3f3f;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int maxn = 10 + 5;
const int mod = 1e9 + 7;
const char *mark = "+-*";
const int dr[] = {-1, 0, 1, 0};
const int dc[] = {0, 1, 0, -1};
int n, m;
inline bool is_in(int r, int c){
    return r >= 0 && r < n && c >= 0 && c < m;
}

int main(){
    int T; cin >> T;
    while(T--){
        int kase;
        scanf("%d %d", &kase, &n);
        LL ans1 = (LL)n*(n+1)/2;
        LL ans2 = (LL)n*(2LL + 2LL*n)/2;
        LL ans3 = (LL)n * (2LL*n)/2;
        printf("%d %lld %lld %lld\n", kase, ans1, ans3, ans2);
    }
    return 0;
}