考虑两个字符串,我们用dp[i][j]表示字串第到i个和字符串到第j个的总数,由于字串必须连续 因此dp[i][j]能够有dp[i][j-1]和dp[i-1][j-1]递推而来,而不能由dp[i-1][j]递推而来.而后者的条件 是字串的第i个和字符串相等. A subsequence of a given sequence is just the given sequence with some elements (possibly none) left out. Formally, give…

题目:uva 10069 Distinct Subsequences 题意:给出一个子串 x 和母串 s .求子串在母串中的不同序列的个数? 分析:定义dp[i][j]:x 的前 i 个字母在 s 的前 j 个字母中的出现次数: dp [ i ] [ j ] = dp [ i ] [ j - 1 ] ;          if ( x[ i ] == s [ j ] )                     dp[i][j]=add(dp[i-1][j-1],dp[i][j]); 注意点:1:…

题目连接:10069 - Distinct Subsequences 题目大意:给出两个字符串x (lenth < 10000), z (lenth < 100), 求在x中有多少个z. 解题思路:二维数组DP, 有类似于求解最长公共子序列, cnt[i][j]表示在x的前j个字符中有多少个z 前i个字符. 状态转移方程 1.x[j] != z[i]              cnt[i][j] = cnt[i][j - 1]; 2.x[j] == z[i]   cnt[i][j] = cnt…

 题意 求母串中子串出现的次数(长度不超过1后面100个0  显然要用大数了) 令a为子串 b为母串 d[i][j]表示子串前i个字母在母串前j个字母中出现的次数   当a[i]==b[j]&&d[i-1][j-1]!=0时 d[i][j]=d[i-1][j-1]+d[i][j-1] (a[i]==b[j]时 子串前i个字母在母串前j个字母中出现的次数 等于 子串前i-1个字母在母串前j-1个字母中出现的次数 加上 子串前i个字母在母串前j-1个字母中出现的次数  a[i]!=b[j]…

Given a string S and a string T, count the number of distinct subsequences ofT inS. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative po…

Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative…

uva 116 Unidirectional TSP Background Problems that require minimum paths through some domain appear in many different areas of computer science. For example, one of the constraints in VLSI routing problems is minimizing wire length. The Traveling Sa…

转载请注明出处: http://www.cnblogs.com/fraud/          ——by fraud Mountain Subsequences Time Limit: 1 Sec  Memory Limit: 128 MB Description Coco is a beautiful ACMer girl living in a very beautiful mountain. There are many trees and flowers on the mountain,…

题目来源:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=3&page=show_problem&problem=39  Stacking Boxes  Background Some concepts in Mathematics and Computer Science are simple in one or two dimensions but become…

UVA 674  Coin Change  解题报告 题目链接:http://acm.hust.edu.cn/vjudge/contest/view.action?cid=87730#problem/E 题目: Suppose there are 5 types of coins: 50-cent, 25-cent, 10-cent, 5-cent, and 1-cent. We want to make changes with these coins for a given amount o…