https://reurl.cc/Ejm7aa
1404. Number of Steps to Reduce a Number in Binary Representation to One
给定一串表示二进制数字的字串
你可对此字串进行两项操作:+1跟/2
请透过两项操作将字串变成1
回传将字串变成1的所需步骤数
Example 1:
Input: s = "1101"
Output: 6
Explanation: "1101" corressponds to number 13 in their decimal representation.
Step 1) 13 is odd, add 1 and obtain 14.
Step 2) 14 is even, divide by 2 and obtain 7.
Step 3) 7 is odd, add 1 and obtain 8.
Step 4) 8 is even, divide by 2 and obtain 4.
Step 5) 4 is even, divide by 2 and obtain 2.
Step 6) 2 is even, divide by 2 and obtain 1.
Example 2:
Input: s = "10"
Output: 1
Explanation: "10" corressponds to number 2 in their decimal representation.
Step 1) 2 is even, divide by 2 and obtain 1.
Example 3:
Input: s = "1"
Output: 0
Constraints:
1 <= s.length <= 500
s consists of characters '0' or '1'
s[0] == '1'
思路:
模拟 应该有数学解 不过我想不出来 哇哇呜呜呜
Python Code:
class Solution:
def numSteps(self, s: str) -> int:
count = 0
while True:
if s == "1":
return count
if "1" not in s[1:]:
return count+len(s)-1
if s[-1] == "1":
s = str(bin(int(s,2)+1)[2:])
count += 1
else:
s = s[:-1]
count += 1