poj2479

Maximum sum

|code--------------------------------------------------------------------------------------------------+
|001| /***************************************************************\                               
|002|  *Author: 小呼                                                                                
|003|  *Created Time: Tue 06 Jul 2010 02:49:20 PM CST                                                 
|004|  *File Name: a.cpp                                                                              
|005|  *Description:动态规划。Max_L[i]表示A[1...i]中最大的连续和，同理               
|006|  *Max_R[i]是指A[i...n]中最大的连续和                                                   
|007| \***************************************************************/                               
|008| //*====================*Head File*====================*\\                                   
|009|                                                                                                 
|010| #include<iostream>                                                                              
|011| #include<stdio.h>                                                                               
|012| #include<stdlib.h>                                                                              
|013| #include<string.h>                                                                              
|014| /*----------------------*Global Variable*----------------------*/                               
|015|                                                                                                 
|016| //*===================*Main Program*===================*//                                  
|017| using namespace std;                                                                            
|018| int A[50001],n,Max_L[50001],Max_R[50001];                                                       
|019| int main(){                                                                                     
|020| .       int T;                                                                                  
|021| .       scanf("%d",&T);                                                                         
|022| .       while(T--){                                                                             
|023| .       .       scanf("%d",&n);                                                                 
|024| .       .       for(int i=1;i<=n;++i)                                                           
|025| .       .         scanf("%d",A+i);                                                              
|026| .       .       int _max=-9999999,temp=-9999999;                                                
|027| .       .       for(int i=1;i<n;++i){                                                           
|028| .       .       .       if(temp>=0)                                                             
|029| .       .       .         temp+=A[i];                                                           
|030| .       .       .       else                                                                    
|031| .       .       .       .       temp=A[i];                                                      
|032| .       .       .       _max=_max>temp?_max:temp;                                               
|033| .       .       .       Max_L[i]=_max;                                                          
|034| .       .       }                                                                               
|035| .       .       _max=temp=-999999;                                                              
|036| .       .       for(int i=n;i>1;--i){                                                           
|037| .       .       .       if(temp>0)                                                              
|038| .       .       .         temp+=A[i];                                                           
|039| .       .       .       else                                                                    
|040| .       .       .         temp=A[i];                                                            
|041| .       .       .       _max=_max>temp?_max:temp;                                               
|042| .       .       .       Max_R[i]=_max;                                                          
|043| .       .       }                                                                               
|044| .       .       int res=-999999;                                                                
|045| .       .       for(int i=1;i<n;++i){                                                           
|046| .       .       .       res=(res>Max_L[i]+Max_R[i+1]?res:Max_L[i]+Max_R[i+1]);                  
|047| .       .       }                                                                               
|048| .       .       printf("%d\n",res);                                                             
|049| .       }                                                                                       
|050| .       return 0;                                                                               
|051| }                                                                                               
end+--------------------------------------------------------------------------------------------------+