H - String painter

 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <cstdio>
 #include <string>
 #include <map>
 #include <cmath>
 #include <vector>

 #define Faster ios::sync_with_stdio(false),cin.tie(0)
 #define Read freopen("in.txt","r",stdin),freopen("out.txt","w",stdout)
 #define Close fclose(stdin),fclose(stdout)
 const int maxn = ;
 using namespace std;
 const int MOD = 1e9+;
 typedef long long ll;

 char s1[maxn];
 char s2[maxn];
 int dp[maxn][maxn];
 int len;
 int ans[maxn];

 int main(){
     Faster;
     while(~scanf("%s%s", s1, s2)){
         len = strlen(s1);
         memset(dp, , sizeof(dp));
         for(int j = ;j < len; j++){    //j为尾
             for(int i = j;i >= ;i--){        //i为头
                 dp[i][j] = dp[i+][j] + ;    //每个都单独刷一次
                 for(int k = i+;k <= j;k++){
                     if(s2[i] == s2[k]){
                         dp[i][j] = min(dp[i][j], (dp[i+][k]+dp[k+][j]));
                     }
                 }
             }
         }
         for(int i = ;i < len;i++){
             ans[i] = dp[][i];
         }
         for(int i = ;i < len;i++){
             if(s1[i] == s2[i]){
                 ans[i] = ans[i-];    //对应位置相等的话，就不用刷新
             }
             else{
                 for(int j = ;j < i;j++){
                     ans[i] = min(ans[i], ans[j] + dp[j+][i]);    //寻找j来分割区间的最优解
                 }
             }
         }
         printf("%d\n", ans[len-]);
     }
     return ;
 }