HDU 3308 线段树 最长连续上升子序列 单点更新 区间查询

题意：

T个测试数据

n个数 q个查询

n个数 ( 下标从0开始)

Q u v 查询 [u, v ] 区间最长连续上升子序列

U u v 把u位置改成v

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define N 101010
#define L(x) (x<<1)
#define R(x) (x<<1|1)
inline int Max(int a,int b){return a>b?a:b;}
inline int Min(int a,int b){return a<b?a:b;}

struct node
{
	int l,r;
	int mid(){ return (l+r)>>1; }
	int len(){ return r-l+1; }
	int Llen, Rlen, maxlen;

}tree[4*N];
int a[N];
void updata_up(int id){
	tree[id].Llen = tree[L(id)].Llen;
	tree[id].Rlen = tree[R(id)].Rlen;
	tree[id].maxlen = Max( tree[L(id)].maxlen, tree[R(id)].maxlen);

	if( a[ tree[L(id)].r ] < a[ tree[R(id)].l ] )
	{
		if( tree[L(id)].Llen == tree[L(id)].len())
		{
			tree[id].Llen += tree[R(id)].Llen;
			tree[id].maxlen = Max( tree[id].maxlen, tree[id].Llen);
		}
		if( tree[R(id)].Rlen == tree[R(id)].len() )
		{
			tree[id].Rlen += tree[L(id)].Rlen;
			tree[id].maxlen = Max( tree[id].maxlen, tree[id].Rlen);
		}
		tree[id].maxlen = Max( tree[id].maxlen, tree[L(id)].Rlen + tree[R(id)].Llen );

	}

}
void build(int l, int r, int id){
	tree[id].l = l,  tree[id].r = r;

	if(l==r){ tree[id].Llen = tree[id].Rlen = tree[id].maxlen =1; return ; }

	int mid = (l+r)>>1;
	build(l,   mid, L(id));
	build(mid+1, r, R(id));
	updata_up(id);
}

void updata(int pos,int id){
	if(tree[id].l == tree[id].r)return ;

	int mid = tree[id].mid();
	if( pos <= mid ) updata(pos, L(id));
	else updata(pos, R(id));
	updata_up(id);
}

int query(int l, int r, int id){
	if( l == tree[id].l && tree[id].r == r)
		return tree[id].maxlen;

	int mid = tree[id].mid();
	if(r <= mid)return query(l, r, L(id));
	else if(mid < l) return query(l, r, R(id));

	int L = query(l, mid, L(id)), R = query(mid+1, r, R(id));

	if( a[mid] < a[mid+1] ){
		int LL = Min( mid - l + 1, tree[L(id)].Rlen);
		int RR = Min( r - mid,     tree[R(id)].Llen);
		return Max( Max(L,R), LL+RR);
	}
	else return Max(L, R);
}

int main(){
	int T,n,q,i; scanf("%d",&T);
	while(T--){
		scanf("%d %d", &n, &q);
		for(i=1;i<=n;i++)scanf("%d",&a[i]);

		build(1, n, 1);
		while(q--)
		{
			char c = '-';
			while(c!='Q' && c!='U') c = getchar();
			int u,v; scanf("%d %d", &u, &v);

			if(c == 'Q')
				printf("%d\n", query(u+1, v+1, 1));
			else if(c == 'U')
			{ a[u+1] = v; updata(u+1, 1); }

		}
	}
	return 0;
}
/*
99
10 10
7 7 3 3 5 9 9 8 1 8
Q 6 6
U 3 4
Q 0 1
Q 0 5
Q 4 7
Q 3 5
Q 0 2
Q 4 6
U 6 10
Q 0 9

10 99
1 2 3 4 5 6 7 8 9 10
Q 4 7
U 0 8
Q 0 9
U 8 8

Q 0 9

*/