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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. const int maxn=1e7+14;
  4. long long n, pre[maxn], k;
  5. int ans = -1;
  6. void solve(){
  7. 	cin >> n >> k;
  8. 	pre[0] = 0;
  9. 	unordered_map < long long , int > m;
  10. 	for (int i = 1; i <= n; i++){
  11. 		int x;
  12. 		cin >> x;
  13. 		pre[i] = (pre[i - 1] + x) % k;
  14. 		if (!m[pre[i]]) m[pre[i]] = i;
  15. 	}
  16. 	m[0] = 0;
  17. 	for (int i = 1; i <= n; i++) {
  18.         if (pre[i] == 0) ans = max(ans, i);
  19. 		if (m[pre[i]]){
  20. 			ans = max(ans, i - m[pre[i]]);
  21. 		}
  22. 	}
  23. 	if (ans == 0 ){
  24. 		cout << -1 ;
  25. 		return ;
  26. 	}
  27.  
  28. 	cout << ans ;
  29. }
  30. int main(){
  31. 	ios_base::sync_with_stdio(0);
  32. 	cin.tie(0);    cout.tie(0);
  33.     if (fopen("input.txt","r")){
  34.         freopen("input.txt","r",stdin);
  35.         freopen("output.txt","w",stdout);
  36.     }
  37. 	solve();
  38. 	return 0;
  39. }
  40.  
Success #stdin #stdout 0.01s 5272KB
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Standard input is empty
stdout
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-1
https://ideone.com/eM7u75
language:
C++14 (gcc 8.3)
created:
343 days ago
visibility:
public

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