FindWordsThatCanBeFormedbyCharacters.java

package string;

import java.util.*;

/**
 * Created by gouthamvidyapradhan on 28/08/2019 You are given an array of strings words and a string
 * chars.
 *
 * <p>A string is good if it can be formed by characters from chars (each character can only be used
 * once).
 *
 * <p>Return the sum of lengths of all good strings in words.
 *
 * <p>Example 1:
 *
 * <p>Input: words = ["cat","bt","hat","tree"], chars = "atach" Output: 6 Explanation: The strings
 * that can be formed are "cat" and "hat" so the answer is 3 + 3 = 6. Example 2:
 *
 * <p>Input: words = ["hello","world","leetcode"], chars = "welldonehoneyr" Output: 10 Explanation:
 * The strings that can be formed are "hello" and "world" so the answer is 5 + 5 = 10.
 *
 * <p>Note:
 *
 * <p>1 <= words.length <= 1000 1 <= words[i].length, chars.length <= 100 All strings contain
 * lowercase English letters only.
 *
 * <p>Solution Do a linear check for each of the words and each of the characters and sum up the
 * lengths. Keep a hashmap of key-values to avoid picking the same character again.
 */
public class FindWordsThatCanBeFormedbyCharacters {
  public static void main(String[] args) {
    String[] A = {"cat", "bt", "hat", "tree"};
    String chars = "atach";
    new FindWordsThatCanBeFormedbyCharacters().countCharacters(A, chars);
  }

  public int countCharacters(String[] words, String chars) {
    Map<Character, Integer> countMap = new HashMap<>();
    for (char c : chars.toCharArray()) {
      countMap.putIfAbsent(c, 0);
      countMap.put(c, countMap.get(c) + 1);
    }
    int ans = 0;
    for (String s : words) {
      Map<Character, Integer> subMap = new HashMap<>();
      for (char c : s.toCharArray()) {
        subMap.putIfAbsent(c, 0);
        subMap.put(c, subMap.get(c) + 1);
      }
      boolean possible = true;
      for (char k : subMap.keySet()) {
        if (!countMap.containsKey(k) || subMap.get(k) > countMap.get(k)) {
          possible = false;
          break;
        }
      }
      if (possible) {
        ans += s.length();
      }
    }
    return ans;
  }
}