You are given a string?s?consisting only of the characters?'0'?and?'1'. In one operation, you can change any?'0'?to?'1'?or vice versa.

The string is called alternating if no two adjacent characters are equal. For example, the string?"010"?is alternating, while the string?"0100"?is not.

Return?the?minimum?number of operations needed to make?s?alternating.

?

Example 1:

Input: s = "0100"

Output: 1

Explanation: If you change the last character to '1', s will be "0101", which is alternating.

Example 2:

Input: s = "10"

Output: 0

Explanation: s is already alternating.

Example 3:

Input: s = "1111"

Output: 2

Explanation: You need two operations to reach "0101" or "1010".

?交替進(jìn)行的話，一共有2種，一種是01開頭，一種是10開頭，分別計(jì)算01跟10開頭的話，不相同的數(shù)量，然后取較小的那個(gè)就是最小的調(diào)整次數(shù)了。

easy題目，有思路就很快了。不麻煩。

Constraints:

• 1 <= s.length <= 104

• s[i]?is either?'0'?or?'1'.

Runtime:?3 ms, faster than?85.71%?of?Java?online submissions for?Minimum Changes To Make Alternating Binary String.

Memory Usage:?42.9 MB, less than?8.11%?of?Java?online submissions for?Minimum Changes To Make Alternating Binary String.