algorithm001
diff --git a/Week_02/id_12/242_12 b/Week_02/id_12/242_12
@@ -0,0 +1,36 @@
+class Solution {
+
+    /**
+     * @param String $s
+     * @param String $t
+     * @return Boolean
+     */
+    function isAnagram($s, $t) {
+        $ttemp = $t;
+        $sLen = strlen($s);
+        $tLen = strlen($t);
+        if($sLen != $tLen){
+            return false;
+        }
+        $sbool = $tbool = true;
+        for($i=0;$i<$sLen;$i++){
+            if(stripos($t, $s[$i]) === false){
+                $sbool = false;
+                break;
+            } 
+            $t = preg_replace("/$s[$i]/", '', $t, 1);
+        }
+        for($j=0;$j<$tLen;$j++){ 
+            if(stripos($s, $ttemp[$j]) === false){
+                $tbool = false;
+                break;
+            }
+            $s = preg_replace("/$ttemp[$j]/", '', $s, 1);
+        }
+        if($sbool && $tbool){
+            return true;
+        }else{
+            return false;
+        }
+    }
+}
diff --git a/Week_02/id_12/671_12 b/Week_02/id_12/671_12
@@ -0,0 +1,31 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int findSecondMinimumValue(TreeNode root) {
+        return traversal(root,root.val);
+    }
+
+    private int traversal(TreeNode root,int value){
+        if(root == null){
+            return -1;
+        }
+        if(root.val > value){
+            return root.val;
+        }
+        int l = traversal(root.left,value);
+        int r = traversal(root.right,value);
+
+        if(l>=0 && r>=0){
+            return Math.min(l,r);
+        }
+        return Math.max(l,r);
+    }
+
+}
diff --git a/Week_03/id_12/104_12 b/Week_03/id_12/104_12
@@ -0,0 +1,15 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int maxDepth(TreeNode root) {
+        if(root == null){return 0;}
+        return Math.max(maxDepth(root.left)+1, maxDepth(root.right)+1);
+    }
+}
diff --git a/Week_03/id_12/997_12 b/Week_03/id_12/997_12
@@ -0,0 +1,31 @@
+class Solution {
+
+    /**
+     * @param Integer $N
+     * @param Integer[][] $trust
+     * @return Integer
+     */
+    function findJudge($N, $trust) {
+        if(count($trust)==1){
+            return $trust[0][1];
+        }
+        if(count($trust)==0){
+            return 1;
+        }
+
+        $countArr = [];
+        foreach($trust as $key=>$val){
+            $countArr[$val[0]] = -1;
+            if($countArr[$val[1]] !=-1){
+                $countArr[$val[1]]++;
+            }
+        }
+
+        for($i=0;$i<=$N;$i++){
+           if($countArr[$i] == $N-1){
+                return $i;
+           }
+        }        
+        return -1;
+    }
+}
diff --git a/Week_04/id_12/LeetCode_169_12.php b/Week_04/id_12/LeetCode_169_12.php
@@ -0,0 +1,19 @@
+class Solution {
+
+    /**
+     * @param Integer[] $nums
+     * @return Integer
+     */
+    function majorityElement($nums) {
+        $numsTem = $maxArr = array();
+        foreach($nums as $key=>$val){
+            if(in_array($val,$numsTem)){
+                $maxArr[$val]++;
+            }else{
+                $numsTem[$val] = $val;
+                $maxArr[$val] = 1;
+            }
+        }
+        return array_search(max($maxArr),$maxArr);    
+    }
+}
diff --git a/Week_04/id_12/LeetCode_455_12.php b/Week_04/id_12/LeetCode_455_12.php
@@ -0,0 +1,24 @@
+class Solution {
+
+    /**
+     * @param Integer[] $g
+     * @param Integer[] $s
+     * @return Integer
+     */
+    function findContentChildren($g, $s) {
+
+        asort($g);
+        asort($s);
+        $g = array_values($g);
+        $s = array_values($s);
+        $child = $cake = 0;
+        while($child < count($g) && $cake < count($s)){
+            if($g[$child] <= $s[$cake]){
+                $child++;
+                var_dump($child);
+            }
+            $cake++;
+        }
+        return $child;
+    }
+}
diff --git a/Week_04/id_12/LeetCode_720_12.php b/Week_04/id_12/LeetCode_720_12.php
@@ -0,0 +1,24 @@
+class Solution {
+
+    /**
+     * @param String[] $words
+     * @return String
+     */
+    function longestWord($words) {
+
+        asort($words);
+        $arrTem = array();
+        $res = '';
+        foreach($words as $key=>$val){
+            $strLen = strlen($val);
+            $strTem = substr($val,0,$strLen-1);
+            if($strLen == 1 || in_array($strTem,$arrTem)){
+                $arrTem[$key] = $val;
+                $res =  $strLen > strlen($res) ? $val : $res;
+            }
+        }
+        return $res;
+
+    }
+
+}