392. Is Subsequence

392. Is Subsequence

• 題目描述：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.

• 題目大意：給定兩個字符串s與t，判斷s是否爲t的子串。

• 思路：思路很簡單直接看代碼

• 代碼

  package DP;
  
  /**
  * @author OovEver
  * 2018/1/3 11:11
  */
  public class LeetCode392 {
    public boolean isSubsequence(String s, String t) {
        if (s.length() == 0) {
            return true;
        }
        int indexS = 0, indexT = 0;
        while (indexT < t.length()) {
            if (s.charAt(indexS) == t.charAt(indexT)) {
                indexS++;
                if (indexS == s.length()) {
                    return true;
                }
            }
  
            indexT++;
        }
        return false;
    }
  }