HDU3308 LCIS

1Y爽歪歪

线段树功能：1. 单点更新 2.查询区间递增子序列长度

 

代码：

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
#define for if(0); else for
const int N=100010;

struct SegNode{
    int lval,rval;
    int lsum,rsum,csum;
    bool flag;
    SegNode(){lval=rval=0,lsum=rsum=csum=1,flag=false;}
};


struct SegTree{
    SegNode a[N<<2];
    int n,Q;
    void Init(int n){
        for(Q=1;Q<=n+2;Q<<=1);
        this->n=n;
        for(int i=0;i<=Q<<1;i++) a[i]=SegNode();
    }
    void pushup(int rt,int L){
        if(rt>=Q) return;
        a[rt]=merge(a[rt<<1],a[rt<<1|1],L);
    }
    SegNode merge(SegNode l,SegNode r,int L){
        if(l.flag==1) return r;
        SegNode ret=SegNode();
        ret.lval=l.lval;
        ret.rval=r.rval;
        ret.lsum=l.lsum;
        ret.rsum=r.rsum;
        ret.csum=max(l.csum,r.csum);
        if(l.rval<r.lval){
            if(ret.lsum==L>>1) ret.lsum+=r.lsum;
            if(ret.rsum==L>>1) ret.rsum+=l.rsum;
            ret.csum=max(ret.csum,l.rsum+r.lsum);
        }
        ret.csum=max(ret.csum,max(ret.lsum,ret.rsum));
        return ret;
    }
    SegNode query(int L,int R,int l,int r,int rt){
        SegNode ret;
        ret.flag=true;
        if(L<=l&& r<=R){
            return a[rt];
        }
        if(rt>=Q) return ret;
        int m=(l+r)>>1;
        if(L<=m) ret=merge(ret,query(L,R,l,m,rt<<1),r-l+1);
        if(m<R) ret=merge(ret,query(L,R,m+1,r,rt<<1|1),r-l+1);
        return ret;
    }
    void update(int pos,int x){
        pos+=Q;
        a[pos].lval=a[pos].rval=x;pos>>=1;
        int L=2;
        while(pos) a[pos]=merge(a[pos<<1],a[pos<<1|1],L),L<<=1,pos>>=1;
    }
    SegNode query(int L,int R){
        return query(L,R,0,Q-1,1);
    }
}st;
int T,n,m;
int main() {
    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&n,&m);
        st.Init(n);
        for(int i=1;i<=n;i++){
            int x;
            scanf("%d",&x);
            st.update(i,x);
        }
        for(int i=1;i<=m;i++){
            char cmd;
            int l,r;
            scanf(" %c %d %d",&cmd,&l,&r);
            if(cmd=='U'){
                st.update(l+1,r);
            }else if(cmd=='Q'){
                SegNode ans=st.query(l+1,r+1);
                printf("%d\n",ans.csum);
            }
        }
    }
    return 0;
}