remove_letter_to_equalize_frequency.cpp

// 删除字符使频率相同
// https://leetcode.cn/problems/remove-letter-to-equalize-frequency
// INLINE  ../../images/map/remove_letter_to_equalize_frequency.jpeg
// 官方题解
#include <headers.hpp>

class Solution {
public:
  // 判断字符串是否可以通过删除一个字符使得每种字符出现频率相同
  bool equalFrequency(string word) {
    int charCount[26] = {0};
    // 统计字符出现次数
    for (char c : word) {
      charCount[c - 'a']++;
    }
    unordered_map<int, int> freqCount;
    // 统计每种出现次数的字符数量
    for (int c : charCount) {
      if (c > 0) {
        freqCount[c]++;
      }
    }
    // 枚举每个字符，判断是否可以删除一个字符使得频率相同
    for (int c : charCount) {
      if (c == 0) {
        continue;
      }
      freqCount[c]--;
      if (freqCount[c] == 0) {
        freqCount.erase(c);
      }
      if (c - 1 > 0) {
        freqCount[c - 1]++;
      }
      if (freqCount.size() == 1) {
        return true;
      }
      if (c - 1 > 0) {
        freqCount[c - 1]--;
        if (freqCount[c - 1] == 0) {
          freqCount.erase(c - 1);
        }
      }
      freqCount[c]++;
    }
    return false;
  }
};