5thweek.problem_a hdu1003 Maximum sub-segments and

Description

Given a sequence a[1],a[2],a[3]......a[n], your job is to calculate the max sum of a sub-sequence. For example, given (6,-1,5,4,-7), the max sum in this sequence is 6 + (-1) + 5 + 4 = 14. 

Input

The first line of the input contains an integer T (1<=t<=20) which means the number of test cases. Then T lines follow, each line starts with a number N (1<=n<=100000), then n integers followed (all the integers is b etween-1000 and 1000). 

Output

For the test case, you should output of the lines. The first line was "Case #:", # means the number of the the test case. The second line contains three integers, the Max Sum in the sequence, the start position of the sub-sequence, the end posi tion of the sub-sequence. If there is more than one result, output the first one. Output a blank line between cases. 

Sample Input

2 5 6-1 5 4-7 7 0 6-1 1-6 7-5

Sample Output

Case 1:14 1 4Case 2:7 1 6 Analysis:DP problem. State transition Equation:dp[i]=d[i-1]+a[i]>a[i]?d[i-1]+a[i]:a[i]; The error code is as follows: (Critical error vs. correct code)

1#include <iostream>2#include <cstdio>3 using namespacestd;4 Const intm=100005;5 intA[m];6 7 intMain ()8 {9     intt,k=0;Tenscanf"%d",&t); One      while(t--) A     { -         intn,i,maxn,before,begin=1, end=1; -scanf"%d",&n); the          for(i=1; i<=n;i++) -         { -  -scanf"%d",&a[i]); +             if(i==1) -              { +Maxn=a[i]; Before=A[i]; A              } at              Else -              { -                 if(before+a[i]<A[i]) -                 { -Before=A[i]; -begin=i; in                 } -                 Else to                 { +before+=A[i]; -                 } the  *              } $              if(before>MAXN)Panax Notoginseng              { -maxn=before; the                   //X=begin; +End=i; A              } the  +         } -k++; $printf"Case %d:\n", k); $printf"%d%d%d\n", maxn,begin,end); -         if(t) -printf"\ n"); the  -     }Wuyi  the     return 0; -}

View Code

The correct code is as follows: (use a special point case 6:2 3-6 4 3-8 to find out the error!) Add a key variable J record current A[i] position)

1#include <iostream>2#include <cstdio>3 using namespacestd;4 Const intm=100005;5 intA[m];6 7 intMain ()8 {9     intt,k=0;Tenscanf"%d",&t); One      while(t--) A     { -         intn,i,maxn,before,begin=1, end=1, j=1;//must use a J to record the position of the current number A[i] -scanf"%d",&n); the          for(i=1; i<=n;i++) -         { -  -scanf"%d",&a[i]); +             if(i==1) -              { +Maxn=a[i]; Before=A[i]; A  at              } -              Else -              { -                 if(before+a[i]<A[i]) -                 { -Before=A[i]; inJ=i;//record the current position at which begin does not change -                 } to                 Else +                 { -before+=A[i]; the                 } *  $              }Panax Notoginseng              if(before>MAXN) -              { themaxn=before; +Begin=j;//only when the BEFORE>MAXN is changed AEnd=i; the              } +  -         } $k++; $printf"Case %d:\n", k); -printf"%d%d%d\n", maxn,begin,end); -         if(t) theprintf"\ n"); - Wuyi     } the  -     return 0; Wu}

5thweek.problem_a hdu1003 Maximum sub-segments and