392. Is Subsequence

  这道题直接依次比较字符就行了，相等就移动，如果s先移完，那说明是子串，如果t先移完，说明不是

  

class Solution {public:bool isSubsequence(string s, string t) {if (s.size() == 0)return 1;if (t.size() == 0)return 0;int j = s.size() - 1;for (int i = t.size() - 1; i >= 0; --i){if (s[j] == t[i])--j;if (j < 0)return 1;}return 0;}};