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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0901_1000.s0926_flip_string_to_monotone_increasing;

// #Medium #String #Dynamic_Programming #2022_03_29_Time_12_ms_(63.41%)_Space_50.7_MB_(48.55%)

/**
 * 926 - Flip String to Monotone Increasing\.
 *
 * Medium
 *
 * A binary string is monotone increasing if it consists of some number of `0`'s (possibly none), followed by some number of `1`'s (also possibly none).
 *
 * You are given a binary string `s`. You can flip `s[i]` changing it from `0` to `1` or from `1` to `0`.
 *
 * Return _the minimum number of flips to make_ `s` _monotone increasing_.
 *
 * **Example 1:**
 *
 * **Input:** s = "00110"
 *
 * **Output:** 1
 *
 * **Explanation:** We flip the last digit to get 00111.
 *
 * **Example 2:**
 *
 * **Input:** s = "010110"
 *
 * **Output:** 2
 *
 * **Explanation:** We flip to get 011111, or alternatively 000111.
 *
 * **Example 3:**
 *
 * **Input:** s = "00011000"
 *
 * **Output:** 2
 *
 * **Explanation:** We flip to get 00000000.
 *
 * **Constraints:**
 *
 * *   1 <= s.length <= 10⁵
 * *   `s[i]` is either `'0'` or `'1'`.
**/
public class Solution {
    public int minFlipsMonoIncr(String s) {
        if (s == null || s.length() <= 1) {
            return 0;
        }
        final int n = s.length();
        int countOnes = 0;
        int countFlips = 0;
        for (int i = 0; i < n; i++) {
            if (s.charAt(i) == '0') {
                if (countOnes == 0) {
                    continue;
                } else {
                    countFlips++;
                }
            } else {
                countOnes++;
            }
            countFlips = Math.min(countFlips, countOnes);
        }
        return countFlips;
    }
}