SRM 698 div1 RepeatString

250pts RepeatString

题意：问最少修改多少次将一个字符串修改为AA的形式。可以插入一个字符，删除一个字符，修改字符。

思路：枚举分界点，然后dp一下。

 /*
 * @Author: mjt
 * @Date:   2018-10-17 19:50:16
 * @Last Modified by:   mjt
 * @Last Modified time: 2018-10-17 20:08:04
 */
 #include<bits/stdc++.h>
 using namespace std;
 typedef long long LL; const int N = ; int f[N][N]; class RepeatString{
 public:
     int solve(int p,string s) {
         memset(f, 0x3f, sizeof(f));
         string a, b;
         a += '#', b += '#';
         for (int i=; i<=p; ++i) a += s[i];
         for (int j=p+; j<(int)s.size(); ++j) b += s[j];
         for (int i=; i<(int)a.size(); ++i) f[i][] = i;
         for (int i=; i<(int)b.size(); ++i) f[][i] = i;         for (int i=; i<(int)a.size(); ++i)
             for (int j=; j<(int)b.size(); ++j) {
                 f[i][j] = min(f[i][j], min(f[i - ][j], f[i][j - ]) + );
                 f[i][j] = min(f[i][j], f[i - ][j - ] + (a[i] != b[j]));
             }
         return f[a.size() - ][b.size() - ];
     }
     int minimalModify(string s) {
         int ans = s.size();
         for (int i=; i<(int)s.size(); ++i) ans = min(ans, solve(i, s));
         return ans - ;
     }
 };