A string of 0s and 1s is monotone increasing if it consists of some number of 0s (possibly 0), followed by some number of 1s (also possibly 0.)
We are given a string S of 0s and 1s, and we may flip any 0 to a 1 or a 1 to a 0.
Return the minimum number of flips to make S monotone increasing.
Example 1:
Input: "00110"
Output: 1
Explanation: We flip the last digit to get 00111.
Example 2:
Input: "010110"
Output: 2
Explanation: We flip to get 011111, or alternatively 000111.
Example 3:
Input: "00011000"
Output: 2
Explanation: We flip to get 00000000.
Note:
1 <= S.length <= 20000
S only consists of 0 and 1 characters.