F Sumo and Luxury Car
题目地址:
基本思路:
根据题意我们由组合数学公式比较容易推出答案为 然后化简一下实际上就是直接快速幂运算就是了。
参考代码:
#pragma GCC optimize(2) #pragma GCC optimize(3) #include <bits/stdc++.h> using namespace std; #define IO std::ios::sync_with_stdio(false) #define int long long #define rep(i, l, r) for (int i = l; i <= r; i++) #define per(i, l, r) for (int i = l; i >= r; i--) #define mset(s, _) memset(s, _, sizeof(s)) #define pb push_back #define pii pair <int, int> #define mp(a, b) make_pair(a, b) #define INF (int)1e18 inline int read() { int x = 0, neg = 1; char op = getchar(); while (!isdigit(op)) { if (op == '-') neg = -1; op = getchar(); } while (isdigit(op)) { x = 10 * x + op - '0'; op = getchar(); } return neg * x; } inline void print(int x) { if (x < 0) { putchar('-'); x = -x; } if (x >= 10) print(x / 10); putchar(x % 10 + '0'); } int mod = 1e9 + 7; int qpow(int a,int x) { int ret = 1; while (x) { if (x & 1) ret = ret * a % mod; a = a * a % mod; x >>= 1; } return ret; } signed main() { //IO; int T; T = read(); while (T--) { int n = read(); int ans = n * qpow(2, n - 1); ans %= mod; print(ans); puts(""); } return 0; }