http://acm.hdu.edu.cn/showproblem.php?pid=2476
String painter
Time Limit: 5000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7666 Accepted Submission(s): 3738
Problem Description
There are two strings A and B with equal length. Both strings are made up of lower case letters. Now you have a powerful string painter. With the help of the painter, you can change a segment of characters of a string to any other character you want. That is, after using the painter, the segment is made up of only one kind of character. Now your task is to change A to B using string painter. What’s the minimum number of operations?
Input
Input contains multiple cases. Each case consists of two lines:
The first line contains string A.
The second line contains string B.
The length of both strings will not be greater than 100.
The first line contains string A.
The second line contains string B.
The length of both strings will not be greater than 100.
Output
A single line contains one integer representing the answer.
Sample Input
zzzzzfzzzzz abcdefedcba abababababab cdcdcdcdcdcd
Sample Output
6 7
Source
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//#include <bits/stdc++.h> #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <iostream> #include <algorithm> #include <iostream> #include <cstdio> #include <string> #include <cstring> #include <stdio.h> #include <queue> #include <stack>; #include <map> #include <set> #include <string.h> #include <vector> #define ME(x , y) memset(x , y , sizeof(x)) #define SF(n) scanf("%d" , &n) #define rep(i , n) for(int i = 0 ; i < n ; i ++) #define INF 0x3f3f3f3f #define mod 998244353 #define PI acos(-1) using namespace std; typedef long long ll ; int dp[200005]; int w[209] , val[209]; int main() { int n ; while(~scanf("%d" , &n)) { for(int i = 0 ; i <= 200000 ; i++) dp[i] = -INF ; dp[100000] = 0 ; for(int i = 1 ; i <= n ; i++) { scanf("%d%d" , &w[i] , &val[i]); } for(int i = 1 ; i <= n ; i++) { if(w[i] < 0 && val[i] < 0) continue ; if(w[i] > 0) { for(int j = 200000 ; j >= w[i] ; j--) { if(dp[j-w[i]] > -INF) dp[j] = max(dp[j] , dp[j-w[i]]+val[i]); } } else { for(int j = w[i] ; j <= 200000 + w[i] ; j++) { if(dp[j-w[i]] > -INF) dp[j] = max(dp[j] , dp[j-w[i]]+val[i]); } } } int ans = -INF ; for(int i = 100000 ; i <= 200000 ; i++) { if(dp[i] >= 0) { ans = max(ans , dp[i]+i-100000); } } cout << ans << endl; } return 0 ; }