20分，8个点WA都显示“Wrong Answer.wrong output format Unexpected end of file - int32 expected”

#include<bits/stdc++.h>
using namespace std;
int n,c,i,j,u;
struct kof{
	int x,ip;
}a[100001];
bool cmp(kof a,kof b)
{
	return a.x>b.x;
}
int main()
{
	cin>>n>>c;
	for(i=1;i<=c;i++)
	cin>>a[i].x,a[i].ip=i;
	sort(a+1,a+c+1,cmp);
	for(i=1;i<=c;i++)
	{
		for(j=i+1;j<=c;j++)
		{
			if(a[i].x>=a[j].x)
			{
				for(u=1;u<=a[j].x;u++)
				{
					if(a[i].ip<a[j].ip)
						printf("%d %d\n",a[i].ip,a[j].ip);
					else
						printf("%d %d\n",a[j].ip,a[i].ip);
				}
				a[i].x-=a[j].x,a[j].x=0;
			}
			else break;
		}
		i=j;
	}
}