HDU 1754 I Hate It (单点替换模板)

//#include<bits/stdc++.h>
#include<stdio.h>
#include<algorithm>
#include<string.h>
using namespace std;

const int MAXN = 200007;
#define lson l , m ,rt<<1
#define rson m+1, r , rt<<1|1
int Max[MAXN<<2];

void Pushup(int rt)
{
    Max[rt] = max(Max[rt<<1],Max[rt<<1|1]);
}

void Build(int l,int r,int rt)
{
    if(l == r)
    {
        scanf("%d",&Max[rt]);
        return;
    }
    int m = (l+r)>>1;
    Build(lson);
    Build(rson);
    Pushup(rt);
}

int Query(int L,int R,int l,int r,int rt)
{
    if(L<=l && R>=r)
        return Max[rt];
    int m = (l+r)>>1;
    int maxn = 0;
    if(L<=m)
        maxn = max(maxn,Query(L,R,lson));
    if(R>m)
        maxn = max(maxn,Query(L,R,rson));
    return maxn;
}

void Update(int num,int val,int l,int r,int rt)
{
    if(l == r)
    {
        Max[rt] = val;
        return;
    }
    int m = (l+r)>>1;
    if(num <= m)
        Update(num,val,lson);
    else Update(num,val,rson);
    Pushup(rt);
}

int main()
{
    int N,M;
    char op[2];
    while(~scanf("%d%d",&N,&M))
    {
        memset(Max,0,sizeof(Max));
        Build(1,N,1);
        while(M--)
        {
            int a,b;
            scanf("%s%d%d",op,&a,&b);
            if(op[0] == 'Q')
                printf("%d\n",Query(a,b,1,N,1));
            else Update(a,b,1,N,1);
        }
    }
    return 0;
}