# ---
# title: 367. Valid Perfect Square
# id: problem367
# author: Tian Jun
# date: 2020-10-31
# difficulty: Easy
# categories: Math, Binary Search
# link: <https://leetcode.com/problems/valid-perfect-square/description/>
# hidden: true
# ---
# 
# Given a **positive** integer _num_ , write a function which returns True if
# _num_ is a perfect square else False.
# 
# **Follow up:** **Do not** use any built-in library function such as `sqrt`.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: num = 16
#     Output: true
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: num = 14
#     Output: false
#     
# 
# 
# 
# **Constraints:**
# 
#   * `1 <= num <= 2^31 - 1`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
