❌ [124] tried...

Author: enkr1

124/my_solution.js

@@ -0,0 +1,72 @@
+class TreeNode {
+  constructor(val, left, right) {
+    this.val = (val === undefined ? 0 : val);
+    this.left = (left === undefined ? null : left);
+    this.right = (right === undefined ? null : right);
+  }
+}
+
+
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+function maxPathSum(root) {
+  let queue = [root], max = root.val;
+
+  const exploreToFindMax = (node) => {
+    if (node === null) return;
+    console.log(`-> v:${node.val}`)
+
+    // let l = node.left, r = node.right;
+    // if (l !== null) {}
+    const defaultForNull = -Infinity;
+
+    let treeLeftVal = 0, exploreLeftVal = defaultForNull;
+    if (node.left !== null) {
+      treeLeftVal = node.left.val;
+      // console.log("exploreToFindMax -> l")
+      exploreLeftVal = node.val + exploreToFindMax(node.left);
+    }
+    //     console.log("treeLeftVal")
+    //     console.log(treeLeftVal)
+    //     console.log("exploreLeftVal")
+    //     console.log(exploreLeftVal)
+
+    let treeRightVal = 0, exploreRightVal = defaultForNull;
+    if (node.right !== null) {
+      treeRightVal = node.right.val;
+      console.log("exploreToFindMax -> r")
+      exploreRightVal = node.val + exploreToFindMax(node.right);
+      console.log("exploreRightVal")
+      console.log(exploreRightVal)
+    }
+
+    let treeMax = node.val + treeLeftVal + treeRightVal; // 0 represents not picking any of them
+
+    max = Math.max(max, treeMax, exploreLeftVal, exploreRightVal);
+    console.log("node.val")
+    console.log(node.val)
+    console.log("node.val + Math.max(exploreLeftVal, exploreRightVal, 0)")
+    console.log(node.val + Math.max(exploreLeftVal, exploreRightVal, 0))
+    return node.val + Math.max(exploreLeftVal, exploreRightVal, 0);
+  };
+
+  while (queue.length > 0) {
+    let curr = queue.shift(), left = curr.left, right = curr.right;
+    if (left !== null) queue.push(left);
+    if (right !== null) queue.push(right);
+    exploreToFindMax(curr);
+  }
+
+  console.log("max")
+  console.log(max)
+  return max;
+}
+
+maxPathSum(
+  new TreeNode(1,
+    new TreeNode(-2),
+    new TreeNode(3)
+  )
+)

124/solution.js

@@ -0,0 +1,48 @@
+class TreeNode {
+  constructor(val, left, right) {
+    this.val = (val === undefined ? 0 : val);
+    this.left = (left === undefined ? null : left);
+    this.right = (right === undefined ? null : right);
+  }
+}
+
+
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+function maxPathSum(root) {
+  let queue = [root], max = root.val;
+
+  const exploreToFindMax = (node) => {
+    if (node === null) return;
+
+    const defaultForNull = -Infinity;
+
+    let treeLeftVal = 0, exploreLeftVal = defaultForNull;
+    if (node.left !== null) {
+      treeLeftVal = node.left.val;
+      exploreLeftVal = node.val + exploreToFindMax(node.left);
+    }
+
+    let treeRightVal = 0, exploreRightVal = defaultForNull;
+    if (node.right !== null) {
+      treeRightVal = node.right.val;
+      exploreRightVal = node.val + exploreToFindMax(node.right);
+    }
+
+    let treeMax = node.val + treeLeftVal + treeRightVal; // 0 represents not picking any of them
+
+    max = Math.max(max, treeMax, exploreLeftVal, exploreRightVal);
+    return node.val + Math.max(exploreLeftVal, exploreRightVal, 0);
+  };
+
+  while (queue.length > 0) {
+    let curr = queue.shift(), left = curr.left, right = curr.right;
+    if (left !== null) queue.push(left);
+    if (right !== null) queue.push(right);
+    exploreToFindMax(curr);
+  }
+
+  return max;
+}

README.md

@@ -45,6 +45,7 @@
 - [128. Longest Consecutive Sequence](./128/)
 - [133. Clone Graph](./133/)
 - [135. Candy](./135/)
+- [124. Binary Tree Maximum Path Sum](./124/)
 - [125. Valid Palindrome](./125/)
 - [141. Linked List Cycle](./141/)
 - [143. Reorder List](./143/)
@@ -148,7 +149,7 @@ Batch create:
 NOTE: JS IS HERE
 -->
 ```ssh
-chapter=209 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
+chapter=124 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
 ```
 > then you can use `x` for quick debug.