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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int long long
  4. const int N=3e5+10;
  5. bool flag1[N],flag2[N];
  6. int n,m,a[N],b[N],ans;
  7. signed main(){
  8. 	cin>>n>>m;
  9. 	for(int i=1;i<=m;i++){
  10. 		cin>>a[i]>>b[i];
  11. 	}
  12. 	for(int i=m;i>=1;i--){
  13. 		if(flag1[a[i]]==0 && flag2[b[i]]==0){
  14. 			ans++;
  15. 		}
  16. 		flag1[a[i]]=1;
  17. 		flag2[b[i]]=1;
  18. 	}
  19. 	cout<<ans;
  20. 	return 0;
  21. }
Success #stdin #stdout 0s 5592KB
comments (?)
stdin
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3 6
1 1
1 2
3 3
3 2
1 3
1 3
stdout
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2
https://ideone.com/Ck3aHr
language:
C++ (gcc 8.3)
created:
3 days ago
visibility:
public

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