46 lines
1.6 KiB
Python
46 lines
1.6 KiB
Python
|
def interpolation_search(array, x):
|
||
|
|
"""
|
||
|
|
Use interpolation search to find a specified integer
|
||
|
|
"""
|
||
|
|
if isinstance(x, int) and isinstance(array, list): # check that x is integer and array is list
|
||
|
|
if len(array) < 1: # if array length is less than 1 print message
|
||
|
|
return False
|
||
|
|
elif len(array) == 1 and x in array: # if x is only element of array return index 0
|
||
|
|
return 0
|
||
|
|
elif len(array) > 1 and x in array: # search if array length > 1 and x is in the array
|
||
|
|
min = 0
|
||
|
|
max = len(array) - 1
|
||
|
|
while min <= max:
|
||
|
|
if array[min] == array[max] == x:
|
||
|
|
return min
|
||
|
|
elif array[min] == array[max] != x:
|
||
|
|
return False
|
||
|
|
else:
|
||
|
|
p = int(min + (x-array[min])*(max-min) / (array[max]-array[min]))
|
||
|
|
if array[p] == x:
|
||
|
|
return p
|
||
|
|
elif x < array[p]:
|
||
|
|
max = p - 1
|
||
|
|
continue
|
||
|
|
elif x > array[p]:
|
||
|
|
min = p + 1
|
||
|
|
continue
|
||
|
|
else:
|
||
|
|
return False # if x is not in array return false
|
||
|
|
else:
|
||
|
|
raise Exception('Please make sure x is an integer and array is a list.')
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
tests = [
|
||
|
|
([1,4,7,10,13,16], 13),
|
||
|
|
([1,4,7,10,13,16], 11),
|
||
|
|
([1,1,1,1,1,1], 1),
|
||
|
|
([0,0,0,1,1,1,1,1,1,2,3,4,5], 1),
|
||
|
|
([24], 24),
|
||
|
|
([], 24)
|
||
|
|
]
|
||
|
|
|
||
|
|
for test in tests:
|
||
|
|
print(interpolation_search(test[0], test[1]))
|