B3666

这该如何改

#include <iostream>
using namespace std;
#define int unsigned long long
const int N=1000010;
int stack[N],size=0;
signed main(){
	int n,v=0;
	scanf("%llu",&n);
	for(int i=1;i<=n;i++){
		int a;
		scanf("%llu",&a);
		if(!size)	stack[size++]=a,v^=i;
		if(stack[size-1]>a){
			stack[size++]=a;
			v^=i;
		}else{
			size=0;stack[size++]=a;
			v=i;
		}
		printf("%llu\n",v);
	}
	return 0;
}