c ++ stl summarized in use in the race

SET

• bzoj2761: [JLOI2011] Unique numbers

• This problem. . .
•  count () usage, the return value is the number of times this occurs, it will only appear 0 and 1 in the set where this can determine whether a value is in the set appeared in
• Code
  

   1 #include <bits/stdc++.h>
   2 #define nmax 50005
   3 
   4 using namespace std;
   5 int n,in;
   6 
   7 int main(){
   8     int t;
   9     scanf("%d",&t);
  10     while(t--){
  11         set <int> st;
  12         scanf("%d",&n);
  13         scanf("%d",&in);
  14         printf("%d",in);
  15         st.insert(in);
  16         for (int i=1; i<n; i++) {
  17             scanf("%d",&in);
  18             if(st.count(in)) continue;
  19             printf(" %d",in);
  20             st.insert(in);
  21         }
  22         printf("\n");
  23     }
  24     return 0;
  25 }

  setset