367 - Valid Perfect Square
Written on November 7, 2017
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Given a positive integer num, write a function which returns True if num is a perfect square else False.
class Solution(object):
def isPerfectSquare(self, num):
"""
:type num: int
:rtype: bool
"""
lo, hi = 1, num
while lo <= hi:
mid = (lo + hi) / 2
val = mid * mid
if val == num:
return True
elif val < num:
lo = mid + 1
else:
hi = mid - 1
return False