I hate it

#include "stdio.h"
#include <cstdio>
#include <climits>

using namespace std;

#define M ((L+R)>>1)
#define lson rt<<1,L,M
#define rson rt<<1|1,M+1,R
#define root 1,1,N
#define max(a,b) ((a>b)?a:b)

const int maxn = 200001;

int maxv[maxn << 2],ql,qr,tar,v,val[maxn];

inline void pushup(int rt)
 {
    maxv[rt] = max(maxv[rt<<1],maxv[rt<<1|1]);
}

void build(int rt,int L,int R)
{
    if(L == R) maxv[rt] = val[L];
    else
    {
        build(lson); build(rson);
        pushup(rt);
    }
}

void update(int rt,int L,int R)
{
    if(L == R) maxv[rt] = v;
    else {

        if(tar <= M) update(lson);
        if(tar > M) update(rson);
        pushup(rt);
    }
}

int query(int rt,int L,int R)
{
    if(ql <= L && qr >= R) return maxv[rt];
    int lv = -INT_MAX,rv = -INT_MAX;
    if(ql <= M) lv = query(lson);
    if(qr > M) rv = query(rson);
    return max(lv,rv);
}

int main()
{
    int N,m;
    char cmd;
    while(~scanf("%d%d",&N,&m))
    {
        for(int i = 1;i <= N;i++)
        scanf("%d",val + i);
        build(root);
        for(int i = 1;i <= m;i++)
         {
            scanf(" %c",&cmd);
            if(cmd == ‘Q‘)
             {
                scanf("%d%d",&ql,&qr);
                printf("%d\n",query(root));
            }
            else
            {
                scanf("%d%d",&tar,&v);
                update(root);
            }
        }
    }
    return 0;
}