AcWing 885. 求组合数 I 动态规划递推求解
原题链接
简单
作者:
Snrise
,
2024-04-08 20:09:29
,
所有人可见
,
阅读 2
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <iostream>
#define endl '\n'
#define int long long
using namespace std;
const int N = 2010;
const int MOD = 1e9 + 7;
int c[N][N];
int n;
signed main(void)
{
std::ios::sync_with_stdio(false);
for (int i = 0; i < N; i++)
{
c[i][0] = c[i][i] = 1;
}
for (int i = 1; i < N; i++)
{
for (int j = 1; j < i; j++)
{
c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % MOD;
}
}
cin >> n;
while (n--)
{
int a, b;
cin >> a >> b;
cout << c[a][b] << endl;
}
return 0;
}