uvalive 4394 string painter （序列dp）

#include<cstdio>  
#include<cstring>  
#include<cmath>  
#include<cstdlib>  
#include<iostream>  
#include<algorithm>  
#include<vector>  
#include<map>  
#include<queue>  
#include<stack> 
#include<string>
#include<map> 
#include<set>
#define eps 1e-6 
#define LL long long  
using namespace std;  
const int maxn = 100 + 5;
const int INF = 0x3f3f3f3f;
char s[maxn], t[maxn];
int cnt[maxn], d[maxn][maxn][30];

int dp(int start, int end, char shua) {
	if(d[start][end][shua-'a'] != -1) return d[start][end][shua-'a'];
	if(start > end) return 0;
	if(start == end) return shua == t[start] ? 0 : 1;
	if(shua == t[end]) return dp(start, end-1, shua);
	int ans = INF;
	for(int i = end; i >= start; i--) {
		if(t[i] == t[end]) ans = min(ans, dp(start, i-1, shua)+dp(i, end, t[end])+1);
	}
	return d[start][end][shua-'a'] = ans;
}

void solve() {
	memset(d, -1, sizeof(d));
	int len = strlen(s);
	cnt[0] = s[0] == t[0] ? 0 : 1;
	for(int i = 1; i < len; i++) {
		if(s[i] == t[i]) cnt[i] = cnt[i-1];
		else {
			cnt[i] = INF;
			for(int j = i; j >= 0; j--){
				if(t[j] == t[i] && s[j] != t[j]) cnt[i] = min(cnt[i], dp(j+1,i-1,t[i])+1+(j>0 ? cnt[j-1]:0)); 
			}
		}
	}
	printf("%d\n", cnt[len-1]);
}


int main() {
	//freopen("input.txt", "r", stdin);
	while(scanf("%s%s", s, t) == 2) {
		solve(); 
	}
	return 0;
}