LCIS HDU

Given n integers.
You have two operations:
U A B: replace the Ath number by B. (index counting from 0)
Q A B: output the length of the longest consecutive increasing subsequence (LCIS) in [a, b].
InputT in the first line, indicating the case number.
Each case starts with two integers n , m(0<n,m<=10 ⁵).
The next line has n integers(0<=val<=10 ⁵).
The next m lines each has an operation:
U A B(0<=A,n , 0<=B=10 ⁵)
OR
Q A B(0<=A<=B< n).
OutputFor each Q, output the answer.Sample Input

1
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

Sample Output

1
1
4
2
3
1
2
5

需要重新做~~~~
半抄半写的情况下，终于对线段树有了一点熟悉。Pushup中对区间的合并，Query中对区间查询时的讨论，都是值得思考的地方！

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define lson l , m , rt << 1
#define rson m+1,r , rt << 1 | 1
using namespace std;

const int maxn=100005;

int n,q,x,y;
int ls[maxn<<2],rs[maxn<<2],no[maxn<<2];
int a[maxn];

void Pushup(int l,int r,int rt){
    ls[rt]=ls[rt<<1],rs[rt]=rs[rt<<1|1];
    no[rt]=max(no[rt<<1],no[rt<<1|1]);
    int m=(l+r)>>1;
    if(a[m]<a[m+1]){
        if(ls[rt]==m-l+1) ls[rt]+=ls[rt<<1|1];
        if(rs[rt]==r-m) rs[rt]+=rs[rt<<1];
        no[rt]=max(no[rt],ls[rt<<1|1]+rs[rt<<1]);
    }
} 

void Build(int l,int r,int rt){
    if(l==r){ no[rt]=ls[rt]=rs[rt]=1; return; }
    int m=(l+r)>>1;
    Build(lson);
    Build(rson);
    Pushup(l,r,rt); 
}

void Update(int l,int r,int rt){
    if(l==r) return;
    int m=(l+r)>>1;
    if(x<=m) Update(lson);
    if(x>m)  Update(rson);
    Pushup(l,r,rt);
}

int Query(int l,int r,int rt){
    if(x<=l&&r<=y) return no[rt];
    int m=(l+r)>>1;
    if(y<=m) return Query(lson);
    if(x>m)  return Query(rson);
    int n1=Query(lson);
    int n2=Query(rson);
    int ans=max(n1,n2);
    if(a[m]<a[m+1]) ans=max(ans,(min(ls[rt<<1|1],y-m)+min(rs[rt<<1],m-x+1)));          //key point!!!!
    return ans;
}

int main()
{   int kase;
    cin>>kase;
    while(kase--){
        scanf("%d%d",&n,&q);
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        Build(1,n,1);
        
        while(q--){
            char op[5];
            scanf("%s%d%d",op,&x,&y);
            ++x;
            if(op[0]=='U'){ a[x]=y; Update(1,n,1); }
            else{ ++y; printf("%d
",Query(1,n,1));} 
        }
    }
    return 0;
}