'commit'

TangDou/AcWing_TiGao/T5/JuZhengChengFa/1305_BF_DP.cpp

@@ -0,0 +1,38 @@
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long LL;
+int n, m, mod;
+const int N = 1e6 + 10;
+int ne[N];    // kmp的ne数组，针对模式串s
+char s[N];    // 模式串s
+int f[N][22]; // dp数组
+
+//原始版本，就是设计密码那道题的代码，可以过4个点，剩余6个点TLE
+int main() {
+    cin >> n >> m >> mod;
+    cin >> s + 1;
+    // kmp
+    for (int i = 2, j = 0; i <= m; i++) {
+        while (j && s[j + 1] != s[i]) j = ne[j];
+        if (s[j + 1] == s[i]) j++;
+        ne[i] = j;
+    }
+
+    //普通dp
+    f[0][0] = 1;
+    for (int k = 0; k < n; k++)
+        for (int i = 0; i < m; i++)
+            for (char c = '0'; c <= '9'; c++) {
+                int j = i;
+                while (j && s[j + 1] != c) j = ne[j];
+                if (s[j + 1] == c) j++;
+                //在kmp过程中进行判断,不能命中m个长度，需要避让
+                if (j < m) f[k + 1][j] = (f[k + 1][j] + f[k][i]) % mod;
+            }
+
+    int res = 0;
+    for (int i = 0; i < m; i++) res = (res + f[n][i]) % mod;
+
+    printf("%d\n", res);
+    return 0;
+}