Data Structures and Algorithm Analysis in C - SVS

Structures, Algorithm Analysis: CHAPTER 2: ALGORITHM ANALYSIS
We see, then, that among the three ways to form a large maximum subsequence, for
our example, the best way is to include elements from both halves. Thus, the
answer is 11. Figure 2.7 shows an implementation of this strategy.
int
max_sub_sequence_sum( int a[], unsigned int n )
{
return max_sub_sum( a, 0, n-1 );
}
int
max_sub_sum( int a[], int left, int right )
{
int max_left_sum, max_right_sum;
int max_left_border_sum, max_right_border_sum;
int left_border_sum, right_border_sum;
int center, i;
/*1*/ if ( left == right ) /* Base Case */
/*2*/ if( a[left] > 0 )
/*3*/ return a[left];
else
/*4*/ return 0;
/*5*/ center = (left + right )/2;
/*6*/ max_left_sum = max_sub_sum( a, left, center );
/*7*/ max_right_sum = max_sub_sum( a, center+1, right );
/*8*/ max_left_border_sum = 0; left_border_sum = 0;
/*9*/ for( i=center; i>=left; i-- )
{
/*10*/ left_border_sum += a[i];
/*11*/ if( left_border_sum > max_left_border_sum )
/*12*/ max_left_border_sum = left_border_sum;
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2006-1-27