1422. Maximum Score After Splitting a String

Problem

Given a string s of zeros and ones, **return the maximum score after splitting the string into two *non-empty* substrings** (i.e. left substring and right substring).

The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.

  Example 1:

Input: s = "011101"
Output: 5 
Explanation: 
All possible ways of splitting s into two non-empty substrings are:
left = "0" and right = "11101", score = 1 + 4 = 5 
left = "01" and right = "1101", score = 1 + 3 = 4 
left = "011" and right = "101", score = 1 + 2 = 3 
left = "0111" and right = "01", score = 1 + 1 = 2 
left = "01110" and right = "1", score = 2 + 1 = 3

Example 2:

Input: s = "00111"
Output: 5
Explanation: When left = "00" and right = "111", we get the maximum score = 2 + 3 = 5

Example 3:

Input: s = "1111"
Output: 3

  Constraints:

• 2 <= s.length <= 500

• The string s consists of characters '0' and '1' only.

Solution (Java)

class Solution {
    public int maxScore(String s) {
        int zeroes = s.charAt(0) == '0' ? 1 : 0;
        int ones = 0;
        for (int i = 1; i < s.length(); i++) {
            if (s.charAt(i) == '1') {
                ones++;
            }
        }
        int maxScore = zeroes + ones;
        for (int i = 1; i < s.length() - 1; i++) {
            if (s.charAt(i) == '0') {
                zeroes++;
            } else {
                ones--;
            }
            maxScore = Math.max(maxScore, zeroes + ones);
        }
        return maxScore;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).