Is Subsequence

检查子序列算法

最新推荐文章于 2021-08-03 18:19:06 发布

转载最新推荐文章于 2021-08-03 18:19:06 发布 · 222 阅读

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本文介绍了一个简单的算法，用于检查一个字符串是否为另一个字符串的子序列。通过遍历长字符串并匹配短字符串的所有字符来实现这一目标。文章提供了一个C++示例代码，展示了如何有效地解决这一问题。

Is Subsequence

description

Given a string s and a string t, check if s is subsequence of t.

You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100).

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 of “abcde” while “aec” is not).

Example 1:
s = “abc”, t = “ahbgdc”
Return true.

Example 2:
s = “axc”, t = “ahbgdc
Return false.

thinking

判断字符串是否为另一字符串的子串，只需遍历一遍即可

solution

class Solution {  
public:  
    bool isSubsequence(string s, string t) 
    {  
        if(s.size()>t.size()) 
            return false;  
        int len1 = s.size(), len2 = t.size(), k1 = 0, k2 = 0;  
        while(k1 < len1 && k2 < len2)  
        {  
            if(s[k1]==t[k2]) k1++;  
            k2++;  
        }  
        return k1 == len1;  
    }  
};