hihocoder 神奇字符串

思路：

暴力，模拟。

实现：

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

 const int INF = 0x3f3f3f3f;

 void str_swap(string & x, int i, int j)
 {
     char tmp = x[i];
     x[i] = x[j];
     x[j] = tmp;
 }

 int cal(string x, string y)
 {
     int s = x.length();
     int t = y.length();
     if (s != t)
         return INF;
     int cnt = ;
     for (int i = ; i < t; i++)
     {
         if (x[i] == y[i])
             continue;
         bool flag = false;
         for (int j = i + ; j < s; j++)
         {
             if (x[j] == y[i])
             {
                 for (int k = j; k > i; k--)
                 {
                     str_swap(x, k, k - );
                     cnt++;
                 }
                 flag = true;
                 break;
             }
         }
         if (!flag)
         {
             return INF;
         }
     }
     return cnt;
 }

 int main()
 {
     string a, b;
     cin >> a >> b;
     int n = b.length();
     int minn = INF;
     for (int i = ; i <= n; i++)
     {
         for (char c = 'a'; c <= 'z'; c++)
         {
             string tmp = b;
             tmp.insert(i, , c);
             minn = min(minn, cal(a, tmp));
         }
     }
     for (int i = ; i < n; i++)
     {
         for (char c = 'a'; c <= 'z'; c++)
         {
             string tmp = b;
             tmp.erase(i, );
             minn = min(minn, cal(a, tmp));
         }
     }
     for (int i = ; i < n; i++)
     {
         for (char c = 'a'; c <= 'z'; c++)
         {
             string tmp = b;
             tmp[i] = c;
             minn = min(minn, cal(a, tmp));
         }
     }
     cout << minn << endl;
     return ;
 }

总结：

学习了string 类 insert(可以在最后一个字符后面的位置插入字符或者字符串), erase方法。