[luoguP2875] [USACO07FEB]牛的词汇The Cow Lexicon（DP）

Posted 2020-09-20 蒟蒻zht的博客

传送门

 

f[i] 表示前 i 个字符去掉多少个 的最优解

直接暴力DP

 

——代码

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 
 5 int n, m, cnt, f[301];
 6 char s[301], a[601][26];
 7 
 8 inline int read()
 9 {
10     int x = 0, f = 1;
11     char ch = getchar();
12     for(; !isdigit(ch); ch = getchar()) if(ch == ‘-‘) f = -1;
13     for(; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + ch - ‘0‘;
14     return x * f;
15 }
16 
17 inline int min(int x, int y)
18 {
19     return x < y ? x : y;
20 }
21 
22 int main()
23 {
24     int i, j, k, l;
25     n = read();
26     m = read();
27     scanf("%s", s + 1);
28     for(i = 1; i <= n; i++) scanf("%s", a[i] + 1);
29     for(i = 1; i <= m; i++)
30     {
31         f[i] = i;
32         for(j = 1; j <= n; j++)
33         {
34             cnt = 0;
35             l = strlen(a[j] + 1);
36             for(k = i; k; k--)
37             {
38                 if(a[j][l] == s[k]) l--;
39                 else cnt++;
40                 if(!l) break;
41             }
42             if(k) f[i] = min(f[i], f[k - 1] + cnt);
43         }
44     }
45     printf("%d\n", f[m]);
46     return 0;
47 }

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