题解 | 平方根

import sys
n=int(sys.stdin.readline().strip())
#方法1：暴力
'''for i in range(1,(n+1)//2+1):
    if i*i<=n and (i+1)**2>n:
        print(i)'''
#方法2：二分
left,right=1,(n+1)//2+1
while left<right:
    mid=(left+right)//2
    if mid**2<n and (mid+1)**2<=n:
        left=mid+1
    elif mid**2>n and (mid-1)<=n:
        right=mid
    elif mid**2<=n and (mid+1)**2>n:
        break
print(mid)