LeetCode/C++/634.cpp at master · strengthen/LeetCode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
__________________________________________________________________________________________________
class Solution {
public:
    int findDerangement(int n) {
        if (n < 2) return 0;
        vector<long long> dp(n + 1, 0);
        dp[1] = 0; dp[2] = 1;
        for (int i = 3; i <= n; ++i) {
            dp[i] = (dp[i - 1] + dp[i - 2]) * (i - 1) % 1000000007;
        }
        return dp[n];
    }
};
__________________________________________________________________________________________________
class Solution {
public:
    int findDerangement(int n) {
        if (n < 2) return 0;
        vector<long long> dp(n + 1, 0);
        dp[1] = 0; dp[2] = 1;
        for (int i = 3; i <= n; ++i) {
            dp[i] = (dp[i - 1] + dp[i - 2]) * (i - 1) % 1000000007;
        }
        return dp[n];
    }
};
__________________________________________________________________________________________________