leetcode

0 class Solution {

1 static const int MOD = 1e9 + 7;

2 static int dp[2][3][100001];

3

4 public:

5 Solution() { memset(dp, 0xFF, sizeof(dp)); }

6 int checkRecord(int n, int a = 0, int l = 0) const {

7 if (n == 0) return 1;

8 if (dp[a][l][n] != -1) return dp[a][l][n];

9

10 int res = checkRecord(n - 1, a, 0);

11 if (l < 2) res = (res + checkRecord(n - 1, a, l + 1)) % MOD;

12 if (a < 1) res = (res + checkRecord(n - 1, a + 1, 0)) % MOD;

13

14 return dp[a][l][n] = res;

15 }

16 };

17

18 int Solution::dp[2][3][100001];