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 = 0;
    for (int i = 0; i < t; i++)
    {
        if (x[i] == y[i])
            continue;
        bool flag = false;
        for (int j = i + 1; j < s; j++)
        {
            if (x[j] == y[i])
            {
                for (int k = j; k > i; k--)
                {
                    str_swap(x, k, k - 1);
                    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 = 0; i <= n; i++)
    {
        for (char c = 'a'; c <= 'z'; c++)
        {
            string tmp = b;
            tmp.insert(i, 1, c);
            minn = min(minn, cal(a, tmp));
        }
    }
    for (int i = 0; i < n; i++)
    {
        for (char c = 'a'; c <= 'z'; c++)
        {
            string tmp = b;
            tmp.erase(i, 1);
            minn = min(minn, cal(a, tmp));
        }
    }
    for (int i = 0; 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 0;
}

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。