Submission #4262030

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Source Code Expand

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 100000;
int num[maxn + 10];
int ji[maxn + 10];
int ou[maxn + 10];
int n;
int main()
{
	freopen("p.in","r",stdin);
	freopen("f.out","w",stdout);
	scanf("%d",&n);
	for(int i = 1;i <= n;++i)
	{
		scanf("%d",&num[i]);
		if(i & 1)
		{
			ji[(i + 1) / 2] = num[i];
		}
		else
		{
			ou[i / 2] = num[i];
		}
	}
	sort(ji + 1,ji + 1 + (n + 1) / 2);
	sort(ou + 1,ou + 1 + n / 2);
	sort(num + 1,num + 1 + n);
	int ans = 0;
	if(n & 1)
	{
		ans = 0;
		int p = 1;
		for(int i = 1;i <= n;i += 2)
		{
			while(num[i] > ji[p] && p < (n + 1) / 2)
				++p;
			if(num[i] != ji[p])
				++ans;
			while(ji[p] < num[i] && p < (n + 1) / 2)
				++p;
		}
	}
	else
	{
		int p = 1;
		for(int i = 1;i < n;i += 2)
		{
			while(num[i] > ji[p] && p < n  / 2)
				++p;
			if(num[i] != ji[p])
				++ans;
			while(ji[p] < num[i] && p < n  / 2)
				++p;
		}
	}
	printf("%d",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:11:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
  freopen("p.in","r",stdin);
                           ^
./Main.cpp:12:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
  freopen("f.out","w",stdout);
                             ^
./Main.cpp:13:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:16:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&num[i]);
                      ^

Judge Result