E Hilbert Sort 分治

#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll f(int n,int x,int y){
	if(n==0)return 1;
	int m = 1<<(n-1);
	if(x<=m&&y<=m){
		return f(n-1,y,x);
	}
	if(x>m&&y<=m){
		return 1ll*m*m+f(n-1,x-m,y);
	}
	if(x<=m&&y>m){
		return 3ll*m*m+f(n-1,2*m-y+1,m-x+1);
	}
	if(x>m&&y>m){
		return 2ll*m*m+f(n-1,x-m,y-m);
	}
}
struct N{
    int x,y;
	ll id;
}p[1000005];
int cmp(N a,N b){
    return a.id<b.id;
}
int main() {
    int n,k, x, y;
    scanf("%d %d", &n,&k); 
    for(int i=1;i<=n;i++){
        scanf("%d %d",&p[i].x,&p[i].y);
        p[i].id = f(k,p[i].x,p[i].y);
    }
    sort(p+1,p+1+n,cmp);
    for(int i=1;i<=n;i++){
        printf("%d %d\n",p[i].x,p[i].y);
    }
    return 0;
}