1941

1941. Check if All Characters Have Equal Number of Occurrences (Easy)

Given a string s, return true if s is a good string, or false otherwise.

A string s is good if all the characters that appear in s have the same number of occurrences (i.e., the same frequency).

 

Example 1:

Input: s = "abacbc"
Output: true
Explanation: The characters that appear in s are 'a', 'b', and 'c'. All characters occur 2 times in s.

Example 2:

Input: s = "aaabb"
Output: false
Explanation: The characters that appear in s are 'a' and 'b'.
'a' occurs 3 times while 'b' occurs 2 times, which is not the same number of times.

 

Constraints:

• 1 <= s.length <= 1000
• s consists of lowercase English letters.

Solution 1.

// OJ: https://leetcode.com/problems/check-if-all-characters-have-equal-number-of-occurrences/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(C) where C is the range of the characters
class Solution {
public:
    bool areOccurrencesEqual(string s) {
        int cnt[26] = {}, mx = 0;
        for (char c : s) {
            mx = max(mx, ++cnt[c - 'a']);
        }
        for (int i = 0; i < 26; ++i) {
            if (cnt[i] && cnt[i] != mx) return false;
        }
        return true;
    }
};