Create 1273-delete-tree-nodes.js

Author: everthis

1273-delete-tree-nodes.js

@@ -0,0 +1,57 @@
+/**
+ * @param {number} nodes
+ * @param {number[]} parent
+ * @param {number[]} value
+ * @return {number}
+ */
+const deleteTreeNodes = function (nodes, parent, value) {
+  const n = nodes
+  const hash = {}
+  hash[0] = new Node(value[0])
+  for (let i = 1; i < n; i++) {
+    hash[i] = new Node(value[i])
+  }
+
+  for (let i = 1; i < n; i++) {
+    const p = parent[i]
+    hash[p].children[i] = hash[i]
+  }
+
+  const r = hash[0]
+  dfs(r)
+  // console.log(n)
+  return cnt(r)
+
+  function dfs(node) {
+    if (node == null) return 0
+    let res = node.sum
+
+    const keys = Object.keys(node.children)
+    for (const k of keys) {
+      res += dfs(hash[k])
+    }
+
+    node.sum = res
+    return res
+  }
+
+  function cnt(node) {
+    if (node == null) return 0
+    if (node.sum === 0) return 0
+    const keys = Object.keys(node.children)
+    let res = 1
+    for (const k of keys) {
+      res += cnt(hash[k])
+    }
+
+    return res
+  }
+}
+
+class Node {
+  constructor(v) {
+    this.val = v
+    this.sum = v
+    this.children = {}
+  }
+}