二维线段树（树套树）

解析待写

例题：2020 CCPC Wannafly Winter Camp Day5 I 题 

代码：

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e3+10;

int n, m1, m2;
int x, y, xl, xr, yl, yr;
ll w;
ll a[N][N];

void add(){
	a[xl][yl] += w;
	a[xl][yr+1] -= w;
	a[xr+1][yl] -= w;
	a[xr+1][yr+1] += w;
}

ll tree[4*N][4*N];

void up_y(int ox, int oy, int l, int r, int f){
	if(l == r){
		if(f) tree[ox][oy] = w;
		else tree[ox][oy] = max(tree[ox<<1][oy], tree[ox<<1|1][oy]);
		return ;
	}
	int mid = l+r >> 1;
	if(y <= mid) up_y(ox, oy<<1, l, mid, f);
	else up_y(ox, oy<<1|1, mid+1, r, f);
	tree[ox][oy] = max(tree[ox][oy<<1], tree[ox][oy<<1|1]);
}

void up_x(int ox, int l, int r){
	if(l == r){
		up_y(ox, 1, 1, n, 1);
		return ;
	}
	int mid = l+r >> 1;
	if(x <= mid) up_x(ox<<1, l, mid);
	else up_x(ox<<1|1, mid+1, r);
	up_y(ox, 1, 1, n, 0);
}

ll qu_y(int ox, int oy, int l, int r){
	if(l >= yl && r <= yr){
		return tree[ox][oy];
	}
	int mid = l+r >> 1;
	ll res = 0;
	if(yl <= mid) res = max(res, qu_y(ox, oy<<1, l, mid));
	if(yr > mid) res = max(res, qu_y(ox, oy<<1|1, mid+1, r));
	return res;
}

ll qu_x(int ox, int l, int r){
	if(l >= xl && r <= xr) {
		return qu_y(ox, 1, 1, n);
	}
	int mid = l+r >> 1;
	ll res = 0;
	if(xl <= mid) res = max(res, qu_x(ox<<1, l, mid));
	if(xr > mid) res = max(res, qu_x(ox<<1|1, mid+1, r));
	return res;
}

int main(){
	scanf("%d%d%d", &n, &m1, &m2);
	while(m1--){
		scanf("%d%d%d%d%lld", &xl, &yl, &xr, &yr, &w);
		add();
	}
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= n; j++){
			a[i][j] += a[i][j-1] + a[i-1][j] - a[i-1][j-1];
			x = i, y = j, w = a[i][j];
			up_x(1, 1, n);
		}
	}
	while(m2--){
		scanf("%d%d%d%d", &xl, &yl, &xr, &yr);
		ll ans = qu_x(1, 1, n);
		printf("%lld\n", ans);
	}
	return 0;
}

 

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标签：xl,树套,int,res,线段,二维,ox,ll,yl
来源： https://blog.csdn.net/qq_43590432/article/details/104149343