HDu-5443-The Water Problem-裸のRMQ線分ツリー

#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <queue>
#include <set>
#include <vector>
#define  inf 0x7fffffff
#define lson l , m , rt << 1
#define rson m + 1 , r , rt << 1 | 1
const int maxn = 1005;

int st_max[maxn<<2];
int aa[maxn];
inline int maxx(int a,int b) { return a>b?a:b; }
void PushUP(int rt)
{
    st_max[rt] = maxx(st_max[rt<<1],st_max[rt<<1|1]);
}
int  ok=0;
void build(int l,int r,int rt) {
    if (l == r)
    {     st_max[rt]=aa[++ok];    
    return ;
    }
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
    PushUP(rt);
}

/*
void update(int l,int r,int rt,int st_max[],int op,int num,int val) 
{
if (l == r&& l==num)
{    
st_max[rt] =val; 
return ;
}
int m = (l + r) >> 1;
if (num<=m)
update(lson,st_max,op,num,val);
else
update(rson,st_max,op,num,val);

  PushUP(rt,l,r,m, st_max,op);
  }
  
*/

int query_max(int qL,int qR,int l,int r,int rt) //L,R ，lr 
{
    if (qL <= l && r <= qR) {
        return st_max[rt];
    }
    int m = (l + r) >> 1;
    int ret1 = -inf,ret2 = -inf;
    if (qL <= m) ret1 = query_max(qL , qR , lson);
    if (qR > m) ret2 = query_max(qL , qR , rson);
    return maxx(ret1,ret2);
}

int main()
{
    int n,m,i,a,b;
    int t;
    scanf("%d",&t);
    while(t--)
    {
        ok=0;
        scanf("%d",&n);
        for (i=1;i<=n;i++) 
            scanf("%d",&aa[i]);
        
        
        build(1 , n , 1);
        scanf("%d",&m);
        for(i=1;i<=m;i++)
        {
            scanf("%d %d",&a,&b);
            printf("%d
",query_max(a,b,1,n,1));
        } 
    }
    return 0;
}