A Simple Code for an Array Search

Paul Xiong
Oct 22, 2020

Sharp my Python coding skills…

As a senior guy in IT, my most time has spent on architecture and “new technologies”, coding skill has shifted to 2nd place. But, occasionally writing a neat and smart code, still make me feel joy.

A matrix question is:

for each row and column, intergers are sort in ascending, from left to right, top to bottom:
find a numer, return false or true:
5, true
100, false

The idea is simple: trying to

  • find the mid-point of a row
  • compare the value of the mid-point to trying-to-find-value
  • narrow down the search range to the left if less or right, if the mid-point is less or greater than tying-to-find-value
  • repeat
        cols= len(matrix[0])
for row in matrix:
midpoint = cols // 2
range_l = 0
range_r = cols
while True:
if row[midpoint] == target:
return True
elif row[midpoint] > target:
range_r = midpoint
elif row[midpoint] < target:
range_l = midpoint
shift = (range_r - range_l) // 2
midpoint = range_l + shift
if shift == 0:
if row[midpoint] == target:
return True
return False

To speed up the performance, the above way isn’t the best, but it is neat and easy to understand to me.



Paul Xiong

Coding, implementing, optimizing ML annotation with self-supervised learning, TLDR: doctor’s labeling is the 1st priority for our Cervical AI project.