Leetcode 1446: Consecutive Characters

In this Leetcode problem, we count the maximum length of consecutive same character in a string.

Problem statement

Solution

Simply put here are the main ideas to resolve the problem:

• Go through the string remembering what character was last encountered last
• Remember the current consecutive streak current
• Remember the maximum number of consecutive same character encountered max
• Be sure to handle edge cases correctly, such as empty string, one character string, strings only containing the same character (eg “aaaaaaa”)

Here is the full solution:

class Solution {
    public int maxPower(String s) {
        int n = s.length();
        if (n < 2) {
            return n;
        }
        char last = ' ';
        int current = 0;
        int max = 1;
        for (int i = 0; i < n; i++) {
            char c = s.charAt(i);
            if (c == last) {
                current++;
                if (current > max) {
                    max = current;
                }
            } else {
                current = 1;
                last = c;
            }
        }
        return max;
    }
}

The algorithm is O(n) with n the length of the string, and O(1) space.

Happy coding :)

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