solves #2287: Rearrange Characters to Make Target String in java

Author: anishLearnsToCode

README.md

@@ -738,7 +738,7 @@
 | 2273 | [Find Resultant Array After Removing Anagrams](https://leetcode.com/problems/find-resultant-array-after-removing-anagrams)                                             |                                                                           [![Java](assets/java.png)](src/FindResultantArrayAfterRemovingAnagrams.java)                                                                           |                                                                                                                                   |
 | 2278 | [Percentage of Letter in String](https://leetcode.com/problems/percentage-of-letter-in-string)                                                                         |                                                                                 [![Java](assets/java.png)](src/PercentageOfLetterInString.java)                                                                                  |                                                                                                                                   |
 | 2283 | [Check if Number Has Equal Digit Count and Digit Value](https://leetcode.com/problems/check-if-number-has-equal-digit-count-and-digit-value)                           |                                                                        [![Java](assets/java.png)](src/CheckIfNumberHasEqualDigitCountAndDigitValue.java)                                                                         |                                                                                                                                   |
-| 2287 | [Rearrange Characters to Make Target String](https://leetcode.com/problems/rearrange-characters-to-make-target-string)                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2287 | [Rearrange Characters to Make Target String](https://leetcode.com/problems/rearrange-characters-to-make-target-string)                                                 |                                                                            [![Java](assets/java.png)](src/RearrangeCharactersToMakeTargetString.java)                                                                            |                                                                                                                                   |
 | 2293 | [Min Max Game](https://leetcode.com/problems/min-max-game)                                                                                                             |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2299 | [Strong Password Checker II](https://leetcode.com/problems/strong-password-checker-ii)                                                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2300 | [Successful Pairs of Spells and Potions](https://leetcode.com/problems/successful-pairs-of-spells-and-potions)                                                         |                                                                        [![Python](assets/python.png)](python/successfull_pairs_of_spells_and_potions.py)                                                                         |                                                                                                                                   |

src/RearrangeCharactersToMakeTargetString.java

@@ -0,0 +1,27 @@
+// https://leetcode.com/problems/rearrange-characters-to-make-target-string
+// T: O(|s| + |target|)
+// S: O(1)
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class RearrangeCharactersToMakeTargetString {
+    public int rearrangeCharacters(String s, String target) {
+        final Map<Character, Integer> sCharFrequencies = getCharFrequencies(s);
+        final Map<Character, Integer> targetCharFrequencies = getCharFrequencies(target);
+
+        int maxCopies = Integer.MAX_VALUE;
+        for (char targetChar : targetCharFrequencies.keySet()) {
+            maxCopies = Math.min(maxCopies, sCharFrequencies.getOrDefault(targetChar, 0) / targetCharFrequencies.get(targetChar));
+        }
+        return maxCopies;
+    }
+
+    private Map<Character, Integer> getCharFrequencies(String string) {
+        final Map<Character, Integer> result = new HashMap<>();
+        for (int i = 0 ; i < string.length() ; i++) {
+            result.put(string.charAt(i), result.getOrDefault(string.charAt(i), 0) + 1);
+        }
+        return result;
+    }
+}