2020牛客寒假算法基础集训营2——C.算概率【DP】

#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn = 2005 + 7;
const int mod = 1e9 + 7;

ll dp[maxn][maxn];	// 前i道题作对j道的概率

ll a[maxn];
int main() {
	int n;	cin >> n;
	for (int i = 1; i <= n; ++i)	cin >> a[i];
	for (int i = dp[0][0] = 1; i <= n; ++i) {
		dp[i][0] = dp[i - 1][0] * (mod + 1 - a[i]) % mod;
		for (int j = 0; j <= n; ++j) {
			dp[i][j] = (dp[i - 1][j] * (mod + 1 - a[i]) + dp[i - 1][j - 1] * a[i]) % mod;
		}
	}
	for (int i = 0; i <= n; ++i)
		cout << dp[n][i] << " ";
}

原文链接：https://blog.youkuaiyun.com/Q_1849805767/article/details/104200360