I Hate It

5 6
1 2 3 4 5
Q 1 5
U 3 6
Q 3 4
Q 4 5
U 2 9
Q 1 5

5
6
5
9

Hint
Huge input,the C function scanf() will work better than cin
 

//500MS	9228K
#include<stdio.h>
#include<algorithm>
using namespace std;
struct Tree
{
    int l,r,mid,count;
}tree[200007*3];
int g[200007];
void build(int left,int right,int i)
{
    tree[i].l=left;tree[i].r=right;tree[i].mid=(left+right)>>1;
    if(left==right){tree[i].count=g[left];return;}
    build(left,tree[i].mid,i*2);
    build(tree[i].mid+1,right,i*2+1);
    tree[i].count=max(tree[2*i].count,tree[2*i+1].count);
}
void update(int id,int num,int i)
{
    if(tree[i].l==tree[i].r&&tree[i].l==id){tree[i].count=num;return;}
    tree[i].count=max(tree[i].count,num);
    if(tree[i*2].r>=id)update(id,num,i*2);
    else update(id,num,i*2+1);
}
int query(int left,int right,int i)
{
    if(tree[i].l==left&&tree[i].r==right)return tree[i].count;
    if(tree[i*2].r>=right)return query(left,right,2*i);
    else if(tree[i*2+1].l<=left)return query(left,right,2*i+1);
    return max(query(left,tree[i].mid,i*2),query(tree[i].mid+1,right,i*2+1));
}
int main()
{
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        for(int i=1;i<=n;i++)
            scanf("%d",&g[i]);
        build(1,n,1);
        while(m--)
        {
            char s[2];
            int a,b;
            scanf("%s%d%d",s,&a,&b);
            if(s[0]=='Q')printf("%d\n",query(a,b,1));
            else update(a,b,1);
        }
    }
    return 0;
}