Maximum sum of consecutive subsequences problem-C#.Net Tutorial-php.cn

Maximum sum of consecutive subsequences problem

巴扎黑

Release： 2016-12-01 09:53:42

Original

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Problem description: Given a sequence a[1], a[2]...a[n], find the maximum value of the sum of elements in its continuous subsequences
For example: 6 -1 5 4 -7 The maximum continuous value of this sequence The sum of the subsequences is 14
See the specific problem: HDOJ 1003 TZU 1202
This problem is also described in "Data Structure and Algorithm Analysis-C Language Description" (authored by Weiss) Chinese version on page 13 (English version on page 18). An algorithm program is given on page 21:

int MaxSubsequenceSum(const int A[], int N)  
{  
  int ThisSum,MaxSum,j;  
  ThisSum = MaxSum = 0;  
  for(j = 0; j < N; j++)  
  {  
    ThisSum += A[j];  
    if(ThisSum > MaxSum)  
      MaxSum = ThisSum;  
    else if(ThisSum < 0)  
      ThisSum = 0;  
   }  
  return MaxSum;  
}

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I wrote the algorithm as follows:

int MaxSubsequenceSum(const int A[], int N)  
{  
  int ThisSum,MaxSum,j;  
  ThisSum =0， MaxSum =INT_MIN;  
  for(j = 0; j < N; j++)  
  {  
    ThisSum += A[j];  
    if(ThisSum > MaxSum)  
      MaxSum = ThisSum;  
    if(ThisSum < 0)  
      ThisSum = 0;  
   }  
  return MaxSum;  
}

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At this time, the else keyword must be deleted, because different values are used for initialization caused by variables. The examples in the book can always ensure that MaxSum is non-negative. And the algorithm I rewrote will have a negative number MaxSum in many cases
My acm program is as follows (both websites above are ac):

#include <stdio.h>  
#include <limits.h>  
  
#define MAX 100000+100  
  
int main(void)  
{  
  int n;  
  int m;  
  int a[MAX];  
  int i,j;  
  int thisSum,maxSum;  
  int maxStart,maxEnd,thisStart;  
  
  scanf("%d",&n);  
  for(i = 1; i <= n; i++)  
    {  
      scanf("%d",&m);  
      for(maxStart=maxEnd=thisStart=thisSum=0,maxSum=INT_MIN,j = 0; j < m; j++)  
    {  
      scanf("%d",&a[j]);  
      thisSum += a[j];  
  
      if(thisSum > maxSum)  
        {  
          maxSum = thisSum;  
          maxStart = thisStart;  
          maxEnd = j;  
        }  
      if(thisSum < 0)  
        {  
          thisSum = 0;  
          thisStart = j+1;  
        }  
    }  
      if(i > 1)  
    printf("\n");  
      printf("Case %d:\n",i);  
      printf("%d %d %d\n",maxSum,maxStart+1,maxEnd+1);  
    }  
  return 0;  
}

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The main part of the program is still the above algorithm, just adding the pair sequence Processing of first and last index numbers.