题目大意:输入字符串a,b,c 要求推断c是否有a,b中的个字符保持原有顺序组合而成. 算法思想: DP 用dp[i][j]表示a的前0~i-1共i个字符和b的前0~j-1共j个字符是否构成c[i+j-1]. 状态转换方程: if(i>=1&&c[i+j-1]==a[i-1]) dp[i][j]=dp[i][j]||dp[i-1][j] if(j>=1&&c[i+j-1]==b[j-1]) dp[i][j]=dp[i][j]||dp[i][j-1] 代码例如以下…

题目链接:http://poj.org/problem?id=2192 思路分析:该问题可以看做dp问题,同时也可以使用dfs搜索求解,这里使用dp解法: 设字符串StrA[0, 1, …, n]和StrB[0,1, .., m]构成字符串Str[0, 1, … , m + n + 1]; 1)状态定义:dp[i, j]表示字符串StrA[0, 1, …, i-1]和字符串StrB[0, 1, .., j-1]构成字符串Str[0, 1, …, i+j-1]: 2)状态转移:如果dp[i-1][…

题意:给定三个串,问c串是否能由a,b串任意组合在一起组成,但注意a,b串任意组合需要保证a,b原串的顺序 例如ab,cd可组成acbd,但不能组成adcb. 分析:对字符串上的dp还是不敏感啊,虽然挺裸的....dp[i][j] 表示a串前i个,b串前j个字母能组成c串前i+j个字母.所以dp[lena-1][lenb-1] = 1; 就行了. 从后往前找就很好找了,从c串最后一个字符开始递归搜索. #include <cstdio> #include <iostream> #i…

题目 刚开始本来觉得可以用队列来写,但是 例如 ta te teta,ta的t先出队列那就不行了,所以还得用dp dp[i][j] 表示A前i个字符与B前j个字符是否能构成C前i+j个字符 要使 dp[i][j] = 1 :需满足 dp[i-1][j] == 1 && C[i+j-1] == A[i-1] 或者 dp[i][j-1] == 1 && C[i+j-1] == B[j-1] #include <iostream> #include <cstdi…

http://poj.org/problem?id=2192 Zipper Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 17585   Accepted: 6253 Description Given three strings, you are to determine whether the third string can be formed by combining the characters in the…

北大ACM - POJ试题分类 -- By EXP 2017-12-03 转载请注明出处: by EXP http://exp-blog.com/2018/06/28/pid-38/ 相关推荐文: 旧版POJ分类目录: http://exp-blog.com/2018/06/10/pid-136/ ACM绝版资源公开( 参考书.模板.讲义.指导): http://exp-blog.com/2018/07/11/pid-1777/ ACM国家集训队论文集(1999-2009): http://ex…

POJ 1401 Factorial Time Limit:1500MS     Memory Limit:65536KB     64bit IO Format:%lld & %llu   Description The most important part of a GSM network is so called Base Transceiver Station (BTS). These transceivers form the areas called cells (this ter…

Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 4748   Accepted: 2078 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…

SudoKu Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%lld & %llu POJ 2676 Description Sudoku is a very simple task. A square table with 9 rows and 9 columns is divided to 9 smaller squares 3x3 as shown on the Figure. In some of the c…

 POJ 3259 Wormholes Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%lld & %llu   Description While exploring his many farms, Farmer John has discovered a number of amazing wormholes. A wormhole is very peculiar because it is a one-way…