Submission #649488

#	Time	Username	Problem	Language	Result	Execution time	Memory
649488		berr	XOR Sum (info1cup17_xorsum)	C++17	0 / 100	815 ms	564 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;


int main()
{
	ios_base::sync_with_stdio(false);

	cin.tie(0);


	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w", stdout);

	int n; cin>>n;

	if(n<5e3)
	{
		int ans=0;

		vector<int> a(n);

		for(int i=0; i<n; i++) cin>>a[i];
		for(int i=0; i<n; i++)
		{
			for(int l=i; l<n; l++)
			{
				ans^=a[i]+a[l];
			}
		}

		cout<<ans;
	}
	else
	{
		int ans=0;
		map<int, int> a;

		for(int i=0; i<n; i++){ int x; cin>>x; a[x]++;}

		for(int i=0; i<5e3; i++)
		{
			for(int l=i; l<5e3; l++)
			{
				if(a.count(l)&&a.count(i))
				{
					if(l==i)
					{
						if((a[l]*a[l])%2) ans^=(l+i);
					}
					
				}
				else
				{
					if((a[l]*a[i])%2) ans^=(l+i);
				}
			}
		}

		cout<<ans;
	}
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:12:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |  freopen("in.txt", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:13:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |  freopen("out.txt", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 38
• Subtask 5: 0 / 23