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
 

Constraints:

1 <= s.length <= 500
s contains only lowercase English letters.

此题让我们求出包含相同字母最长的子串，遍历一次即可。写了个O(N)的算法，居然还有速度更快的算法，难道有不遍历就能解出来的算法？

class ConsecutiveCharacters : public Solution {
public:
    void Exec() {
        auto res = maxPower("leetcode");
    }
    int maxPower(string s) {
        const char *prev = nullptr;
        int curCount = 0, maxCount = 0;

        for (int i = 0; i < s.size(); i++) {
            if (prev == nullptr || *prev == s[i]) {
                curCount++;
            } else {
                if (curCount > maxCount) {
                    maxCount = curCount;
                }
                curCount = 1;
            }
            prev = &s[i];
        }
        if (curCount > maxCount) {
            maxCount = curCount;
        }
        return maxCount;
    }
};