1446. Consecutive Characters

Given a string s, the power of the string is the maximum length of a non-empty substring that contains only one unique character.

Return the power of the string.

 

Example 1:

Input: s = "leetcode"
Output: 2
Explanation: The substring "ee" is of length 2 with the character 'e' only.

Example 2:

Input: s = "abbcccddddeeeeedcba"
Output: 5
Explanation: The substring "eeeee" is of length 5 with the character 'e' only.

Example 3:

Input: s = "triplepillooooow"
Output: 5

Example 4:

Input: s = "hooraaaaaaaaaaay"
Output: 11

Example 5:

Input: s = "tourist"
Output: 1

class Solution {
    public int maxPower(String s) {
        if(s == null) return 0;
        if(s.length() <= 1) return s.length();
        int res = 1;
        char[] ch = s.toCharArray();
        int cursum = 1;
        for(int i = 1; i < ch.length; i++){
            if(ch[i] != ch[i-1]){
                cursum = 1;
            }
            else{
                cursum++;
                res = Math.max(res, cursum);
            }
        }
        return res;
    }
}

题意是找最长连续相等字符。从i=1开始和左边比较，如果不相等就从1重新开始，否则就cursum++。

class Solution {
    public int maxPower(String s) {
        int left = 0, n = s.length(), res = 0;
        char[] ch = s.toCharArray();
        for(int right = 0; right < n; right++) {
            if(ch[right] != ch[left]) {
                while(left < right) left++;
            }
            res = Math.max(res, right - left + 1);
        }
        return res;
    }
}

用sliding window，如果两个不相同就把left移动到right的位置