深度优先和广度优先

let root = {  value: 5,  left: {    value: 4,    left: {      value: 11,      left: {        value: 7,        left: null,        right: null      },      right: {        value: 2,        left: null,        right: null      }    },    right: null  },  right: {    value: 8,    left: {      value: 13,      left: null,      right: null    },    right: {      value: 4,      left: null,      right: {        value: 1,        left: null,        right: null      }    }  }}

// 深度优先function hasPathSum (root, sum) {  if (root == null) {    return false  }  if (root.left == null && root.right == null) {    return root.value === sum  }  return hasPathSum(root.left, sum - root.value) || hasPathSum(root.right, sum - root.value)}

// 广度优先function hasPathSum (root, sum) {  if (root === null) {    return false  }  let node = [root]  let value = [root.value]  while (node.length) {    let now = node.shift()    let temp = value.shift()    if (temp === sum) {      return true    }    if (now.left && now.left !== null) {      node.push(now.left)      value.push(now.left.value + temp)    }    if (now.right && now.right !== null) {      node.push(now.right)      value.push(now.right.value + temp)    }  }  return false}

// 深度优先function binaryTree (root) {  let paths = []  let construct_paths = (root, path) => {    if (root) {      path += root.value.toString()      if (root.left === null && root.right === null) {        paths.push(path)      } else {        // 当前节点不是叶子节点，继续递归        path += '->'        construct_paths(root.left, path)        construct_paths(root.right, path)      }    }  }  construct_paths(root, '')  return paths}// [ '5->4->11->7', '5->4->11->2', '5->8->13', '5->8->4->1' ]

// 广度优先function binaryTree (root) {  if (root === null) {    return false  }  let node = [root]  let value = [root.value]  let paths = []  while (node.length) {    let now = node.shift()    let temp = value.shift()    if (now.left === null && now.right === null) {      paths.push(temp)    }    if (now.left && now.left !== null) {      node.push(now.left)      value.push(temp  + '->'+ now.left.value)    }    if (now.right && now.right !== null) {      node.push(now.right)      value.push(temp  + '->'+ now.right.value)    }  }  return paths}