poj3356

与最长公共子序列相似，dp.

注意循环的范围，不要总是想都不想就用小于。这题就应该用小于等于。

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
using namespace std;

#define maxn 1001

int len1, len2;
string st1, st2;
int f[maxn][maxn];

int main()
{
	//freopen("D:\\t.txt", "r", stdin);
	while (cin >> len1 >> st1 >> len2 >> st2)
	{
		memset(f, 0, sizeof(f));
		for (int i = 0; i <= len1; i++)
			f[i][0] = i;
		for (int i = 0; i <= len2; i++)
			f[0][i] = i;
		for (int i = 1; i <= len1; i++)
			for (int j = 1; j <= len2; j++)
				f[i][j] = min(min(f[i - 1][j] + 1, f[i][j - 1] + 1), f[i - 1][j - 1] + (st1[i - 1] != st2[j - 1]));
		cout << f[len1][len2] << endl;
	}
	return 0;
}