Ransom Note

Author: nikoo28

src/main/java/leetcode/easy/RansomNote.java

@@ -0,0 +1,25 @@
+package leetcode.easy;
+
+public class RansomNote {
+
+  boolean canConstruct(String ransomNote, String magazine) {
+    int[] charCount = new int[26];
+
+    // Count the frequency of each character in the magazine
+    for (char c : magazine.toCharArray()) {
+      charCount[c - 'a']++;
+    }
+
+    // Check if we can construct the ransom note
+    for (char c : ransomNote.toCharArray()) {
+      if (charCount[c - 'a'] == 0) {
+        return false; // Character not available in magazine
+      }
+      charCount[c - 'a']--;
+    }
+
+    // Ransom note can be constructed
+    return true;
+  }
+
+}

src/test/java/leetcode/easy/RansomNoteTest.java

@@ -0,0 +1,35 @@
+package leetcode.easy;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class RansomNoteTest {
+
+  private final RansomNote ransomNote;
+
+  RansomNoteTest() {
+    ransomNote = new RansomNote();
+  }
+
+  @Test
+  void testCanConstruct1() {
+    String ransomNoteStr = "a";
+    String magazineStr = "b";
+    assertFalse(ransomNote.canConstruct(ransomNoteStr, magazineStr));
+  }
+
+  @Test
+  void testCanConstruct2() {
+    String ransomNoteStr = "aa";
+    String magazineStr = "ab";
+    assertFalse(ransomNote.canConstruct(ransomNoteStr, magazineStr));
+  }
+
+  @Test
+  void testCanConstruct3() {
+    String ransomNoteStr = "aa";
+    String magazineStr = "aab";
+    assertTrue(ransomNote.canConstruct(ransomNoteStr, magazineStr));
+  }
+}