一开始第一反映是用暴搜+回溯剪枝,妥妥的超时,见numDistinct0函数。
后来想到这跟公共子串有点类似,满足最优子结构和重叠问题,因此可用DP。
状态转移方程如下:
{ dp[i-1,j-1]+dp[i-1][j] , 当s[i]==s[j],0
dp[i,j]={ dp[i-1][j], 当s[i]!=s[j] ,0
...
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其他好文 时间:
2014-11-09 23:51:47
阅读次数:
256
Given a stringSand a stringT, count the number of distinct subsequences ofTinS.A subsequence of a string is a new string which is formed from the orig...
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其他好文 时间:
2014-10-30 07:06:13
阅读次数:
171
题目:给两个字符串S和T,判断T在S中出现的次数。
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 positions of the remaining characters. (ie, "ACE" is a subsequence...
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其他好文 时间:
2014-10-19 17:09:51
阅读次数:
190
[leetcode]Given a string S and a string T, count the number of distinct subsequences of T in S....
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其他好文 时间:
2014-10-15 13:53:50
阅读次数:
147
Given 3 strings of only lowercase letter you have to count the number of ways you can construct the third string by combining two subsequences from the first two strings.
After deleting ...
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其他好文 时间:
2014-10-10 02:06:23
阅读次数:
174
原题地址:https://oj.leetcode.com/problems/distinct-subsequences/题意:Given a stringSand a stringT, count the number of distinct subsequences ofTinS.A subseq...
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编程语言 时间:
2014-10-08 00:56:04
阅读次数:
262
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 non...
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其他好文 时间:
2014-10-02 16:03:39
阅读次数:
188
求S中和T相同的子串的个数。
递推公式:
dp(i,j):S[0...i-1]和T[0...j-1]中不同子串的个数。
dp(0,j) = 0
dp(i,0) = 1
一般情况下
dp(i,j) = dp(i-1,j-1) + dp(i-1,j) S[i-1] == T[j-1],保留S[i-1]以及丢弃S[i-1]
= dp(i-1,j)...
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其他好文 时间:
2014-09-26 19:57:38
阅读次数:
153
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 ] )
...
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其他好文 时间:
2014-09-17 18:45:42
阅读次数:
327
Distinct Subsequences
Total Accepted: 15484 Total
Submissions: 62324My Submissions
Given a string S and a string T, count the number of distinct subsequences of T in S.
A subsequence of ...
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其他好文 时间:
2014-09-16 22:09:51
阅读次数:
204