0926.flip-string-to-monotone-increasing

926. Flip String to Monotone Increasing

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. 1 <= S.length <= 20000
2. S only consists of 0 and 1 characters.