Add week 04 solutions for merge, max depth, find min

Author: JAEKWANG97

find-minimum-in-rotated-sorted-array/jaekwang97.java

@@ -0,0 +1,18 @@
+class Solution {
+    public int findMin(int[] nums) {
+        int left = 0;
+        int right = nums.length - 1;
+
+        while (left < right) {
+            int mid = left + (right - left) / 2;
+
+            if (nums[mid] > nums[right]) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+
+        return nums[left];
+    }
+}

maximum-depth-of-binary-tree/jaekwang97.java

@@ -0,0 +1,25 @@
+class Solution {
+    private int max;
+
+    public int maxDepth(TreeNode root) {
+        if (root == null) {
+            return 0;
+        }
+
+        max = 0;
+        dfs(root, 1);
+
+        return max;
+    }
+
+    private void dfs(TreeNode node, int depth) {
+        if (node == null) {
+            return;
+        }
+
+        max = Math.max(max, depth);
+
+        dfs(node.left, depth + 1);
+        dfs(node.right, depth + 1);
+    }
+}

merge-two-sorted-lists/jaekwang97.java

@@ -0,0 +1,32 @@
+class Solution {
+    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+        ListNode dummy = new ListNode();
+        ListNode tail = dummy;
+
+        while (list1 != null && list2 != null) {
+            if (list1.val <= list2.val) {
+                tail.next = new ListNode(list1.val);
+                list1 = list1.next;
+            } else {
+                tail.next = new ListNode(list2.val);
+                list2 = list2.next;
+            }
+
+            tail = tail.next;
+        }
+
+        while (list1 != null) {
+            tail.next = new ListNode(list1.val);
+            tail = tail.next;
+            list1 = list1.next;
+        }
+
+        while (list2 != null) {
+            tail.next = new ListNode(list2.val);
+            tail = tail.next;
+            list2 = list2.next;
+        }
+
+        return dummy.next;
+    }
+}