hdu 5443 (2015长春网赛G题 求区间最值)

求区间最值，数据范围也很小，因为只会线段树，所以套了线段树模板=.=

Sample Input
3
1
100
1
1 1
5
1 2 3 4 5
5
1 2
1 3
2 4
3 4
3 5
3
1 999999 1
4
1 1
1 2
2 3
3 3

Sample Output
100
2
3
4
4
5
1
999999
999999
1

 

# include <iostream>
# include <cstdio>
# include <cstring>
# include <algorithm>
# include <cmath>
# include <queue>
# define LL long long
using namespace std ;

const int maxn = 1010;

int MAX[maxn<<2] ; //结点开4倍

void PushUP(int rt) //更新到父节点
{
    MAX[rt] = max(MAX[rt * 2] , MAX[rt * 2 + 1] ); //rt 为当前结点
}

void build(int l , int r , int rt) //构建线段树
{
    if (l == r)
    {
        scanf("%d" , &MAX[rt]) ;
        return ;
    }
    int m = (l + r) / 2 ;
    build(l , m , rt * 2) ;
    build(m + 1 , r , rt * 2 +1) ;
    PushUP(rt) ;
}


int query(int L , int R , int l , int r , int rt)  //区间求最大值
{
    if (L <= l && r <= R)
        return MAX[rt] ;
    int m = (l + r) / 2 ;
    int ret = 0 ;
    if (L <= m)
       ret = max(ret , query(L , R , l , m , rt * 2) ) ;
    if (R > m)
       ret = max(ret , query(L , R , m + 1 , r , rt * 2 + 1) );
    return ret ;
}

int main ()
{
    //freopen("in.txt","r",stdin) ;
    int n , m ;
    int T ;
    scanf("%d" , &T) ;
    while(T--)
    {
        scanf("%d" , &n) ;
        build(1 , n , 1) ;
        scanf("%d" , &m) ;
        while(m--)
        {
            int a , b ;
            scanf("%d %d" , &a , &b) ;
            printf("%d\n", query(a , b , 1 , n , 1))  ;
        }
    }

    return 0 ;
}