add JS solution for 0035 0098 0104

Author: limbowandering

solution/0035.Search Insert Position/Solution.js

@@ -0,0 +1,42 @@
+var searchInsert2 = function (nums, target) {
+  for (let i = 0; i < nums.length; i++) {
+    if (nums[i] >= target) {
+      return i;
+    }
+  }
+  return nums.length;
+}
+
+var searchInsert = function (nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+
+  if (target < nums[left]) {
+    return 0;
+  } else if (target > nums[right]) {
+    return right + 1;
+  }
+
+  let count = 0;
+
+  while (left < right) {
+    if (left + 1 == right) {
+      if (nums[left] < target) {
+        return left + 1;
+      } else {
+        return left;
+      }
+    }
+
+    let mid = Math.floor((left + right) / 2);
+    if (nums[mid] < target) {
+      left = mid;
+    } else if (nums[mid] > target) {
+      right = mid;
+    } else {
+      return mid;
+    }
+  }
+
+  return left;
+}

solution/0098.Validate Binary Search Tree/Solution.js

@@ -0,0 +1,28 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {boolean}
+ */
+var isValidBST = function(root) {
+  if (root == null) return true
+  let arr = []
+  inOrderTraverse(root, arr)
+  for (let i = 0; i < arr.length - 1; i++) {
+    if (arr[i] >= arr[i + 1]) return false
+  }
+  return true
+}
+
+var inOrderTraverse = function(node, arr) {
+  if (node !== null) {
+    inOrderTraverse(node.left, arr)
+    arr.push(node.val)
+    inOrderTraverse(node.right, arr)
+  }
+}

solution/0104.Maximum Depth of Binary Tree/Solution.js

@@ -0,0 +1,33 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function(root) {
+  if (!root) return 0
+  let depth = 1
+  return search(root,depth)
+};
+
+function search(root, depth) {
+  if (!root.left && !root.right) {
+    return depth
+  } else if (root.left && !root.right) {
+    return search(root.left, depth + 1)
+  } else if (root.right && !root.left) {
+    return search(root.right, depth + 1)
+  } else if (root.left && root.right) {
+    return Math.max(search(root.left, depth+1), search(root.right,depth+1))
+  }
+}
+
+var maxDepth2 = function(root) {
+  if (!root) return 0
+  return Math.max(maxDepth(root.left),maxDepth(root.right)) + 1
+}