524. Longest Word in Dictionary through Deleting

Given a string and a string dictionary, find the longest string in the dictionary that can be formed by deleting some characters of the given string. If there are more than one possible results, return the longest word with the smallest lexicographical order. If there is no possible result, return the empty string.

Example 1:
Input:
s = “abpcplea”, d = [“ale”,”apple”,”monkey”,”plea”]

Output:
“apple”
这道题就是先把每一个d内的单词和s的字母比较，s的每一次比较索引都要i++，而d只需要在和s找到一样的字母才需要，每次一次遍历结束后，都要把rel和d[index]进行比较，如果长度是rel比较短，则要更新rel，如果rel长度和d[index]相等，且rel的字典序比d[index]的大，则也要更新rel。
代码如下：

class Solution {public:    string findLongestWord(string s, vector<string>& d) {        string rel="";        for(int index=0;index<d.size();index++){            int i=0,j=0;            for(;i<s.size()&&j<d[index].size();i++){                if(s[i]==d[index][j])j++;            }            if(d[index].size()==j&&((rel.size()<d[index].size())||(rel.size()==d[index].size()&&rel>d[index]))){                rel=d[index];            }        }        return rel;    }};