51 lines
1.5 KiB
C++
51 lines
1.5 KiB
C++
// Source : https://leetcode.com/problems/is-subsequence/
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// Author : Hao Chen
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// Date : 2016-09-08
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/***************************************************************************************
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*
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* Given a string s and a string t, check if s is subsequence of t.
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*
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* You may assume that there is only lower case English letters in both s and t. t is
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* potentially a very long (length ~= 500,000) string, and s is a short string (
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*
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* A subsequence of a string is a new string which is formed from the original string
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* by deleting some (can be none) of the characters without disturbing the relative
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* positions of the remaining characters. (ie, "ace" is a subsequence of "abcde" while
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* "aec" is not).
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*
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* Example 1:
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* s = "abc", t = "ahbgdc"
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*
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* Return true.
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*
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* Example 2:
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* s = "axc", t = "ahbgdc"
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*
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* Return false.
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*
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* Follow up:
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* If there are lots of incoming S, say S1, S2, ... , Sk where k >= 1B, and you want to
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* check one by one to see if T has its subsequence. In this scenario, how would you
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* change your code?
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***************************************************************************************/
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class Solution {
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public:
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bool isSubsequence(string s, string t) {
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if (s.size() <= 0) return true;
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int ps=0, pt=0;
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while (pt < t.size()) {
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if (s[ps] == t[pt]) {
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ps++; pt++;
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if (ps >= s.size()) return true;
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}else {
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pt++;
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}
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}
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return false;
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}
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};
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