loj2016 「SCOI2016」美味

trie 树思想运用到主席树上orz

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, a[200005], cnt, rot[200005], bb, xx, uu, vv;
struct Node{
	int l, r, sum;
}nd[5000005];
int build(int l, int r){
	int o=++cnt;
	if(l==r)	;
	else{
		int mid=(l+r)>>1;
		nd[o].l = build(l, mid);
		nd[o].r = build(mid+1, r);
	}
	return o;
}
int update(int o, int l, int r, int x){
	int re=++cnt;
	nd[re] = nd[o];
	nd[re].sum++;
	if(l==r)	;
	else{
		int mid=(l+r)>>1;
		if(x<=mid)	nd[re].l = update(nd[o].l, l, mid, x);
		else	nd[re].r = update(nd[re].r, mid+1, r, x);
	}
	return re;
}
bool query(int p, int o, int l, int r, int x, int y){
	if(x>y)	return 0;
	if(l>=x && r<=y)	return nd[o].sum-nd[p].sum>0;
	else{
		int mid=(l+r)>>1;
		bool fla=false;
		if(x<=mid)	fla |= query(nd[p].l, nd[o].l, l, mid, x, y);
		if(mid<y)	fla |= query(nd[p].r, nd[o].r, mid+1, r, x, y);
		return fla;
	}
}
int main(){
	cin>>n>>m;
	rot[0] = build(0, 100000);
	for(int i=1; i<=n; i++){
		scanf("%d", &a[i]);
		rot[i] = update(rot[i-1], 0, 100000, a[i]);
	}
	while(m--){
		scanf("%d %d %d %d", &bb, &xx, &uu, &vv);
		int ans=0;
		for(int i=17; i>=0; i--){
			int now=ans+((bb&(1<<i))^(1<<i));
			int nowr=now+(1<<i)-1;
			if(query(rot[uu-1], rot[vv], 0, 100000, max(now-xx,0), min(nowr-xx,100000)))	ans = now;
			else	ans += bb&(1<<i);
		}
		printf("%d\n", ans^bb);
	}
	return 0;
}