Submission #97866

#	Time	Username	Problem	Language	Result	Execution time	Memory
97866		mohammedehab2002	XOR Sum (info1cup17_xorsum)	C++11	100 / 100	1018 ms	21768 KiB

xorsum

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
vector<int> v;
int f(unsigned int x)
{
	int r=v.size(),ans=0;
	for (int l=0;l<v.size();l++)
	{
		r=max(r,l);
		while (r>l && v[l]+v[r-1]>=x)
		r--;
		ans^=(r-l)%2;
	}
	return ans;
}
int main()
{
	int n,ans=0;
	scanf("%d",&n);
	for (int i=0;i<n;i++)
	{
		int a;
		scanf("%d",&a);
		v.push_back(a);
	}
	sort(v.begin(),v.end());
	for (unsigned int i=(1<<29);i;i/=2)
	{
		vector<int> v1,v2;
		for (int j:v)
		{
			if (j<2*i)
			v1.push_back(j);
			else
			v2.push_back(j-2*i);
		}
		v.clear();
		merge(v1.begin(),v1.end(),v2.begin(),v2.end(),back_inserter(v));
		int cnt=(f(4*i)^f(3*i)^f(2*i)^f(i));
		ans+=i*cnt;
	}
	printf("%d",ans);
}

Compilation message (stderr)

xorsum.cpp: In function 'int f(unsigned int)':
xorsum.cpp:9:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int l=0;l<v.size();l++)
               ~^~~~~~~~~
xorsum.cpp:12:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (r>l && v[l]+v[r-1]>=x)
xorsum.cpp: In function 'int main()':
xorsum.cpp:34:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (j<2*i)
        ~^~~~
xorsum.cpp:21:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
xorsum.cpp:25:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a);
   ~~~~~^~~~~~~~~

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