hdu 4107当卡段树「建议收藏」

大家好，又见面了，我是全栈君。

其核心思想是记录最大的节点值和最低值，假设max<p要么min>=p时间，在节点只变化add值，不要子树遍历；否则，就往子树递归。

代码语言：javascript复制

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<vector>

using namespace std;

const int maxn = 2e5 50;
int N, P;

struct node{
	int l, r, Min, Max, add;
	int mid() { return (l r)/2; }
}tree[maxn<<2];

int p, n;
void buildTree(int l, int r, int rt)
{
	tree[rt].l = l;
	tree[rt].r = r;
	tree[rt].add = 0;
	tree[rt].Min = 0;
	tree[rt].Max = 0;
	if(l == r) return ;
	int mid = tree[rt].mid();
	buildTree(l, mid, rt<<1);
	buildTree(mid 1, r, rt<<1|1);
}

void update(int l, int r, int rt, int L, int R, int add)
{
	if(L <= l && R >= r)
	{
		if(tree[rt].Max < P)
		{
			tree[rt].add  = add;
			tree[rt].Min  = add;
			tree[rt].Max  = add;
			return ;
		}
		else if(tree[rt].Min >= P)
		{
			tree[rt].add  = 2*add;
			tree[rt].Min  = 2*add;
			tree[rt].Max  = 2*add;
			return ;
		}
	}
	if(tree[rt].add){
		tree[rt<<1].add  = tree[rt].add;
		tree[rt<<1].Min  = tree[rt].add;
		tree[rt<<1].Max  = tree[rt].add; 
		tree[rt<<1|1].add  = tree[rt].add;
		tree[rt<<1|1].Min  = tree[rt].add;
		tree[rt<<1|1].Max  = tree[rt].add;
		
		tree[rt].add = 0;
	}
	if(l == r) return ;
	int mid = tree[rt].mid();
	if(L <= mid) update(l, mid, rt<<1, L, R, add);
	if(R > mid) update(mid 1, r, rt<<1|1, L, R, add);
	
	tree[rt].Min = min(tree[rt<<1].Min, tree[rt<<1|1].Min);
	tree[rt].Max = max(tree[rt<<1].Max, tree[rt<<1|1].Max);
} 

void query(int l, int r, int rt)
{
	if(tree[rt].Min == tree[rt].Max){
		for(int i = l; i <= r; i   )
			printf( i == N ? "%dn" : "%d ", tree[rt].Min );
		return ;
	}
	if(tree[rt].add)
	{
		tree[rt<<1].add  = tree[rt].add;
		tree[rt<<1].Min  = tree[rt].add;
		tree[rt<<1].Max  = tree[rt].add; 
		tree[rt<<1|1].add  = tree[rt].add;
		tree[rt<<1|1].Min  = tree[rt].add;
		tree[rt<<1|1].Max  = tree[rt].add;
		
		tree[rt].add = 0;
	}	
	if(l == r) return ;
	int mid = tree[rt].mid();
	query(l, mid, rt<<1);
	query(mid 1, r, rt<<1|1);
}

int main()
{
	int n, m, p;
	int a, b, c;
	while(~scanf("%d%d%d", &n, &m, &p))
	{
		N = n;
		P = p;
		buildTree(1, n, 1);
		for(int i = 0; i < m; i   )
		{
			scanf("%d%d%d", &a, &b, &c);
			update(1, n, 1, a, b, c);
		}
		query(1, n, 1);
	}
} 

add max min 递归 全栈

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