solves throne inheritance in java

Author: anishLearnsToCode

Diff for: README.md

@@ -583,6 +583,7 @@
 | 1588 | [Sum of All Odd Length Subarrays](https://leetcode.com/problems/sum-of-all-odd-length-subarrays)                                                          |                                                           [![Java](assets/java.png)](src/SumOfAllOddLengthSubArrays.java)                                                            |                                                                                                                                   |
 | 1592 | [Rearrange Spaces Between Words](https://leetcode.com/problems/rearrange-spaces-between-words)                                                            |                                                           [![Java](assets/java.png)](src/RearrangeSpacesBetweenWords.java)                                                           |                                                                                                                                   |
 | 1598 | [Crawler Log Folder](https://leetcode.com/problems/crawler-log-folder)                                                                                    |                                                                [![Java](assets/java.png)](src/CrawlerLogFolder.java)                                                                 |                                                                                                                                   |
+| 1600 | [Throne Inheritance](https://leetcode.com/problems/throne-inheritance)                                                                                    |                                                                [![Java](assets/java.png)](src/ThroneInheritance.java)                                                                |                                                                                                                                   |
 | 1603 | [Design Parking System](https://leetcode.com/problems/design-parking-system)                                                                              |                                                               [![Java](assets/java.png)](src/DesignParkingSystem.java)                                                               |                                                                                                                                   |
 | 1608 | [Special Array With X Elements Greater Than or Equal X](https://leetcode.com/problems/special-array-with-x-elements-greater-than-or-equal-x)              |                                                  [![Java](assets/java.png)](src/SpecialArrayWithXElementsGreaterThanEqualToX.java)                                                   |                                                                                                                                   |
 | 1614 | [Maximum Nesting Depth of the Parentheses](https://leetcode.com/problems/maximum-nesting-depth-of-the-parentheses)                                        |                                                       [![Java](assets/java.png)](src/MaximumNestingDepthOfTheParentheses.java)                                                       |                                                                                                                                   |

Diff for: src/ThroneInheritance.java

@@ -0,0 +1,63 @@
+// https://leetcode.com/problems/throne-inheritance
+// N = people in royal family
+// birth() T: O(1)
+// death() T: O(1)
+// getInheritanceOrder T: O(N)
+// S: O(N)
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ThroneInheritance {
+    private static final class Person {
+        private final String name;
+        private boolean isAlive = true;
+        private final List<Person> children = new ArrayList<>();
+
+        Person(String name) {
+            this.name = name;
+        }
+
+        void markDead() {
+            this.isAlive = false;
+        }
+
+        void addChild(Person child) {
+            this.children.add(child);
+        }
+    }
+
+    private final Map<String, Person> royalFamily = new HashMap<>();
+    private final Person king;
+
+    public ThroneInheritance(String kingName) {
+        king = new Person(kingName);
+        royalFamily.put(kingName, king);
+    }
+
+    public void birth(String parentName, String childName) {
+        Person child = new Person(childName);
+        royalFamily.put(childName, child);
+        royalFamily.get(parentName).addChild(child);
+    }
+
+    public void death(String name) {
+        royalFamily.get(name).markDead();
+    }
+
+    public List<String> getInheritanceOrder() {
+        final List<String> names = new ArrayList<>();
+        getInheritanceOrder(king, names);
+        return names;
+    }
+
+    public void getInheritanceOrder(Person person, List<String> names) {
+        if (person == null) return;
+        if (person.isAlive) names.add(person.name);
+        for (Person child : person.children) {
+            getInheritanceOrder(child, names);
+        }
+    }
+}