_1002.java

package com.fishercoder.solutions;

import java.util.ArrayList;
import java.util.List;

/**
 * 1002. Find Common Characters
 *
 * Given an array A of strings made only from lowercase letters,
 * return a list of all characters that show up in all strings within the list (including duplicates).
 * For example, if a character occurs 3 times in all strings but not 4 times, you need to include that character three times in the final answer.
 *
 * You may return the answer in any order.
 *
 * Example 1:
 * Input: ["bella","label","roller"]
 * Output: ["e","l","l"]
 *
 * Example 2:
 * Input: ["cool","lock","cook"]
 * Output: ["c","o"]
 *
 * Note:
 *
 * 1 <= A.length <= 100
 * 1 <= A[i].length <= 100
 * A[i][j] is a lowercase letter
 */
public class _1002 {
  public static class Solution1 {
    public List<String> commonChars(String[] A) {
      int[][] charCount = new int[A.length][26];
      for (int i = 0; i < A.length; i++) {
        for (char c : A[i].toCharArray()) {
          charCount[i][c - 'a']++;
        }
      }
      List<String> result = new ArrayList<>();
      for (int i = 0; i < 26; i++) {
        while (charCount[0][i] != 0) {
          char c = (char) (i + 'a');
          boolean valid = true;
          charCount[0][i]--;
          for (int j = 1; j < A.length; j++) {
            if (charCount[j][i] == 0) {
              valid = false;
              break;
            } else {
              charCount[j][i]--;
            }
          }
          if (!valid) {
            break;
          } else {
            result.add("" + c);
          }
        }
      }
      return result;
    }
  }
}