hdu1753I Hate It（线段树）

http://acm.hdu.edu.cn/showproblem.php?pid=1754

单点更新，区间求最值

// File Name: hdu1754.cpp// Author: bo_jwolf// Created Time: 2013年08月16日 星期五 11点27分03秒#include<vector>#include<list>#include<map>#include<set>#include<deque>#include<stack>#include<bitset>#include<algorithm>#include<functional>#include<numeric>#include<utility>#include<sstream>#include<iostream>#include<iomanip>#include<cstdio>#include<cmath>#include<cstdlib>#include<cstring>#include<ctime>using namespace std;#define lson l , mid , rt << 1 #define rson mid + 1 , r , rt << 1 | 1 const int maxn = 200005 ;//int sum[ maxn << 2 ] ;struct node{int Max ;}tree[ maxn << 2 ] ;void PushUp( int rt ){tree[ rt ].Max  = max( tree[ rt << 1 ].Max , tree[ (rt << 1 | 1 ) ].Max ) ;}void build( int l , int r , int rt ){if( l == r ){scanf( "%d" , &tree[ rt ].Max );return ;}int mid = ( l + r ) >> 1 ;build( lson ) ;build( rson ) ;PushUp( rt ) ;}void update( int p , int add , int l , int r , int rt ){if( l == r ){tree[ rt ].Max  = add ;return ;}int mid = ( l + r ) >> 1 ;if( p <= mid )update( p , add , lson ) ;elseupdate( p , add , rson ) ;PushUp( rt ) ;}int query( int L , int R , int l , int r , int rt ){if( L <= l && r <=R ){return tree[ rt ].Max ;}int mid = ( l + r ) >> 1 ;int ret = 0 ; if( L <= mid )ret = max( ret , query( L , R , lson ) ) ;if( R > mid )ret = max( ret , query( L , R , rson ) );return ret ;}int main(){int T , n , m ; while( scanf( "%d%d" , &n , &m ) != EOF ){build( 1 , n , 1 ) ;char op[ 10 ] ;while( m-- ){scanf( "%s" , op ) ;int a , b ;scanf( "%d%d" , &a , &b ) ;if( op[ 0 ] == 'Q' )printf( "%d\n" , query( a , b , 1 , n , 1 ) ) ;elseupdate( a , b , 1 , n , 1 ) ;}}return 0;}