849. Maximize Distance to Closest Person ——weekly contest 87

 1 int maxDistToClosest(vector<int>& seats) {
 2         vector<int> pre,post;
 3         int n = seats.size();
 4         pre.assign(n,0);
 5         post.assign(n,0);
 6         int nst = -200000;
 7         for(int i = 0; i < n; i++){
 8             if(seats[i] == 1){
 9                 nst = i;
10             }else{
11                 pre[i] = i - nst;
12             }
13         }
14         nst = 200000;
15         for(int i = n - 1; i >= 0; i--){
16             if(seats[i]==1){
17                 nst = i;
18             }else{
19                 post[i] = nst - i;
20             }
21         }
22         int res = 0;
23         for(int i = 0; i<n; i++ ){
24             int temp = min(pre[i],post[i]);
25             res = max(res,temp);
26         }
27         return res;
28     }