题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=2476 题目大意: 给出两个等长的串S, T, 要将S变成T, 每次可以把S的连续的一段变成相同的字母,求最少操作数. 这题网上看了好多题解,理解了好久, 记录一下我的理解吧. 首先求出把空串变成T的最少次数. dp[i][j] 表示把空串变成T[i ... j]的最少次数. 首先dp[i][j] = dp[i + 1][j]. 然后有一个性质.如果两次染色的区间有交, 那么小的区间一定完全包含于大…

HDU - 2476 思路:分解问题,先考虑从一个空串染色成 B串的最小花费 ,区间DP可以解决这个问题 具体的就是,当 str [ l ] = = str [ r ]时 dp [ L ] [ R ] = min (dp [ L + 1] [ R ],dp [ L ] [ R-1 ] ) 其他情况可以选择任意一个断点 tmp = min ( tmp , dfs ( l  ,k ) + dfs ( k+1 , r ) ); 接下来就是第二步 现在A串不是空串 ,但然把它当做空串去染是没有问题的,…

String painter Time Limit: 5000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2792 Accepted Submission(s): 1272 Problem Description There are two strings A and B with equal length. Both strings are made up of lo…

String painter Time Limit: 5000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2520    Accepted Submission(s): 1134 Problem Description There are two strings A and B with equal length. Both strings are made up…

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.…

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.…

题意:给出两个串a和b,一次只能将一个区间刷一次,问最少几次能让a=b 思路:首先考虑最坏的情况,就是先将一个空白字符串刷成b需要的次数,直接区间DP[i][j]表示i到j的最小次数. 再考虑把a变成b的次数 ans[i]:a从(0,i)变成b(0,i)所需的最小次数 初始化ans[i]=dp[0][i] 如果a[i]==b[i],则ans[i]=ans[i-1]; 由小区间更新到大区间 //#pragma comment(linker, "/STACK:167772160")//手动…

题意:容易理解. 分析:以后碰到这种类型的题,就要考虑把矩阵先按行来处理,再按列处理.先算出每行能够能够得到的最大值,然后按列处理即可. 代码实现: #include<stdio.h> #include<string.h> int n,m; ],dp[][],b[]; int max(int x,int y) { return x>y?x:y; } int main() { int i,j,res; while(scanf("%d%d",&n,&a…

补一下codeforces前天教育场的题.当时只A了一道题. 大致题意: 定义一个x - y - counter :是一个加法计数器.初始值为0,之后可以任意选择+x或者+y而我们由每次累加结果的最后一位生成一个数列. 例如:4 - 2 - counter 进行+4 +4 +4 +4 +2 +4操作会生成数列 04824.每步要加上x或y是任意的. 给你一个数列(由0~9组成的字符串),问你0~9中全部两个数字生成这个包含这个子串的数列中间至少要插入多少数字.以10 * 10矩阵格式输出. 例如…

其实这个dp过程有点似懂非懂...代码如下: #include <stdio.h> #include <algorithm> #include <string.h> using namespace std; + ; char a[N],b[N]; int dp[N][N]; int f[N]; int main() { ) == ) { ); scanf(); ;i<=n;i++) dp[i][i] = ; ;len<=n;len++) { ;i+len-&…