UVa 11552 DP Fewest Flops

题解

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;

 const int maxn =  + ;
 const int maxm = ;

 int n, k;

 char s[maxn];
 int d[maxn][maxm];

 int cnt[maxn];
 bool vis[maxn][maxm];

 int main()
 {
     int T; scanf("%d", &T);
     while(T--)
     {
         scanf("%d %s", &k, s);
         n = strlen(s);

         memset(d, 0x3f, sizeof(d));
         memset(cnt, , sizeof(cnt));
         memset(vis, false, sizeof(vis));
         for(int i = ; i < n; i += k)
         {
             for(int j = ; j < k; j++)
             {
                 int ch = s[i + j] - 'a';
                 if(!vis[i][ch]) cnt[i]++;
                 vis[i][ch] = true;
             }
         }

         for(int i = ; i < ; i++) if(vis[][i]) d[][i] = cnt[];

         for(int i = k; i < n; i += k)
             for(int j = ; j < ; j++) if(vis[i][j])
                 for(int t = ; t < ; t++) if(vis[i - k][t])
                 {
                     if(vis[i][t] && (j != t || cnt[i] == ))
                         d[i][j] = min(d[i][j], d[i-k][t] + cnt[i] - );
                     else
                         d[i][j] = min(d[i][j], d[i-k][t] + cnt[i]);
                 }

         int ans = n;
         for(int i = ; i < ; i++) ans = min(ans, d[n - k][i]);
         printf("%d\n", ans);
     }

     return ;
 }

代码君