Half-fold Search Algorithm

Half-fold Search Algorithm

 

Algorithm Analysis: data elements are ordered. Three variables, low, mid, and high, are used to save the sequence numbers of the beginning, center, and end of the array elements,

Compare the Key value with a [mid] to narrow down the search scope until the search is successful or fails.

Code:

1 while (low <= high) 2 {3 mid = (high + low)/2; 4 if (a [mid] = x) 5 return mid; 6 else if (a [mid]> x) 7 high = mid-1; // "mid-1" → "-" 8 else // "mid + 1" → "+" Prevent the program from entering an infinite loop
9 low = low + 1;
10}