Binary Tree Longest Consecutive Sequence II

Description

null

Solution(javascript)

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var longestConsecutive = function(root) {
    let max = 0
  const aux = (node) => {
      if(!node) {
          return [null, 0, 0]
      }
      const [leftVal, leftInCount, leftDeCount] = aux(node.left)
      const [rightVal, rightInCount, rightDeCount] = aux(node.right)
      const val = node.val
      let inCount = 1
      let deCount = 1
      if(node.val === leftVal + 1) {
          inCount = leftInCount + 1
      }
      if(node.val === rightVal +1) {
           inCount = Math.max(inCount, rightInCount+1)
      }
      if(node.val === leftVal - 1) {
          deCount = leftDeCount + 1
      }
      if(node.val === rightVal - 1) {
           deCount = Math.max(deCount, rightDeCount+1)
      }
      max = Math.max(
          leftInCount, leftDeCount, 
          rightInCount, rightDeCount,
          inCount,
          deCount,
          max
      )
      if(val === leftVal + 1 && val === rightVal - 1) {
          max = Math.max(max, leftInCount + rightDeCount + 1)
      }
      if(val === leftVal - 1 && val === rightVal + 1) {
          max = Math.max(max, leftDeCount + rightInCount + 1)
      }
      return [node.val, inCount, deCount]
  }
  aux(root)
    return max
};