BST

Author: adaugochi

leetcode/binary-trees/lowest-common-ancestor/adaa-mgbede.php

@@ -0,0 +1,24 @@
+<?php
+
+class Solution {
+    /**
+     * @param TreeNode $root
+     * @param TreeNode $p
+     * @param TreeNode $q
+     * @return TreeNode
+     */
+    function lowestCommonAncestor($root, $p, $q) {
+        if(!$root) return null;
+
+        if($root->val == $p->val || $root->val == $q->val) {
+            return $root;
+        }
+
+        $left = $this->lowestCommonAncestor($root->left, $p, $q);
+        $right = $this->lowestCommonAncestor($root->right, $p, $q);
+
+        if(!$left) return $right;
+        if(!$right) return $left;
+        return $root;
+    }
+}

leetcode/heap-sort/sort-an-array/adaa-mgbede.php

@@ -46,7 +46,6 @@ function stringMatching($s, $t) {
 
     $s = sortStr($s);
     $t = sortStr($t);
-    str_replace()
 
     for($i = 0; $i <= ($m - $n); $i++) {
 

leetcode/queues/implement-queue-using-stacks/adaa-mgbede.php

@@ -0,0 +1,74 @@
+<?php
+
+class MyQueue {
+    public $front = -1;
+    public $rear = -1;
+    public $arr = [];
+
+    /**
+     * Initialize your data structure here.
+     */
+    function __construct() {
+    }
+
+    /**
+     * Push element x to the back of queue.
+     * @param Integer $x
+     * @return NULL
+     */
+    function push(int $x) {
+        if ($this->empty()) {
+            $this->front = $this->rear = 0;
+        } else {
+            $this->rear = $this->rear + 1;
+        }
+        $this->arr[$this->rear] = $x;
+        return null;
+    }
+
+    /**
+     * Removes the element from in front of queue and returns that element.
+     * @return Integer
+     */
+    function pop(): int
+    {
+        $temp = $this->front;
+        if ($this->front == $this->rear) {
+            $this->front = $this->rear = -1;
+        } else {
+            $this->front = $this->front + 1;
+        }
+
+        return $this->arr[$temp];
+    }
+
+    /**
+     * Get the front element.
+     * @return Integer
+     */
+    function peek(): int
+    {
+        return $this->arr[$this->front];
+    }
+
+    /**
+     * Returns whether the queue is empty.
+     * @return Boolean
+     */
+    function empty(): bool
+    {
+        if ($this->front == -1 && $this->rear == -1) {
+            return true;
+        }
+        return false;
+    }
+}
+
+$obj = new MyQueue();
+$obj->push(1);
+$obj->pop();
+$obj->push(2);
+//$obj->peek();
+print_r($obj->peek()); exit;
+
+

leetcode/queues/orderly-queue/adaa-mgbede.php

@@ -0,0 +1,54 @@
+<?php
+
+class SolutionOQ {
+
+    public $front = 0;
+    public $rear = -1;
+    public $arr = [];
+
+    /**
+     * Push element x to the back of queue.
+     * @param String $x
+     * @return NULL
+     */
+    function push(string $x) {
+        $this->rear += 1;
+        $this->arr[$this->rear] = $x;
+    }
+
+    /**
+     * Removes the element from in front of queue and returns that element.
+     */
+    function pop()
+    {
+        $temp = $this->front;
+        $this->front += 1;
+        return $this->arr[$temp];
+    }
+
+    /**
+     * @param String $S
+     * @param Integer $K
+     * @return String
+     */
+    function orderlyQueue(string $S, int $K): string
+    {
+        if ($S == "") return "";
+
+        $this->arr = str_split($S);
+        $this->rear = count($this->arr) - 1;
+
+        for ($i = 0; $i <= $K; $i++) {
+            $x = $this->pop();
+            $this->push($x);
+        }
+        $result = "";
+        for ($i = $this->front; $i <= $this->rear; $i++) {
+            $result .= $this->arr[$i];
+        }
+        return $result;
+    }
+}
+
+$obj = new SolutionOQ();
+echo $obj->orderlyQueue("cba", 1);