Leetcode-5086 Smallest Subsequence of Distinct Characters(不同字符的最小子序列)

 1 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 2 class Solution
 3 {
 4     public:
 5         string smallestSubsequence(string text)
 6         {
 7             int vis[26];
 8             deque<char> deque1;
 9             map<char,int> map1;
10 
11             deque1.clear();
12             map1.clear();
13             int len=text.size();
14             for(int i=0; i<len; i++)
15             {
16                 vis[text[i]-‘a‘]=0;
17                 map1[text[i]]++;
18             }
19             for(int i=0; i<len; i++)
20             {
21                 map1[text[i]]--;
22                 if(vis[text[i]-‘a‘])
23                     continue;
24                 while(!deque1.empty()&&deque1.back()>text[i]&&map1[deque1.back()]>0)
25                 {
26                     vis[deque1.back()-‘a‘]=0;
27                     deque1.pop_back();
28                 }
29                 deque1.push_back(text[i]);
30                 vis[text[i]-‘a‘]=1;
31             }
32             string rnt;
33             while(!deque1.empty())
34             {
35                 rnt += deque1.front();
36                 deque1.pop_front();
37             }
38             return rnt;
39         }
40 };