hdu1754

各种错误都尝试过了，最终是没有考虑多组数据

#include<iostream>
#include<queue>
#include<algorithm>
#include<cstdio>
#include<cstring>
#define size 600100
using namespace std;
int sum[size],ret =0;

void buildtree(int rt,int L,int R)
{
    if(L==R)
    {
        scanf("%d",&sum[rt]);
        getchar();
        return ;
    }
    int mid = (L+R)/2;
    buildtree(rt*2,L,mid);
    buildtree(rt*2+1,mid+1,R);
    if(sum[rt*2]>sum[rt*2+1])sum[rt] = sum[rt*2];
    else sum[rt] = sum[rt*2+1];
}

void update(int x,int y,int L,int R,int rt)
{
    //cout<<"fewffew";
    if(L==R)
    {
        sum[rt] = y;
        return ;
    }
    int mid = (L+R)/2;
    if(x<=mid)
        update(x,y,L,mid,rt*2);
    else
        update(x,y,mid+1,R,rt*2+1);
    if(sum[rt*2]>sum[rt*2+1])sum[rt] = sum[rt*2];
    else sum[rt] = sum[rt*2+1];
}

int query(int rt,int l,int r,int L,int R)
{
    if(L<=l&&r<=R)
    {
        return sum[rt];
    }
    int mid = (l+r)/2;
    if(L<=mid){
        int z = query(rt*2,l,mid,L,R);
        ret = ret>z?ret:z;
    }
    if(R>mid){
        int z =query(rt*2+1,mid+1,r,L,R);
        ret = ret>z?ret:z;
    }
    return ret;
}

int main()
{
    int n,m,a,b;
    while(scanf("%d%d",&n,&m)!=EOF){
    buildtree(1,1,n);
    while(m--)
    {
        ret =0;
        char s[2];
        scanf("%s",s);
        scanf("%d%d",&a,&b);
        getchar();
        if(s[0]=='Q')
        {
            printf("%d\n",query(1,1,n,a,b));
        }
        else
        {
            update(a,b,1,n,1);
        }
    }
    }
    return 0;
}