Create 2581-count-number-of-possible-root-nodes.js

Author: everthis

2581-count-number-of-possible-root-nodes.js

@@ -0,0 +1,45 @@
+/**
+ * @param {number[][]} edges
+ * @param {number[][]} guesses
+ * @param {number} k
+ * @return {number}
+ */
+const rootCount = function (edges, guesses, k) {
+  const lookup = new Set(guesses.map(([a, b]) => a * 1_000_000 + b))
+  const adjList = edges.reduce(
+    (adjList, [a, b]) => {
+      adjList[a].push(b)
+      adjList[b].push(a)
+      return adjList
+    },
+    new Array(edges.length + 1).fill(0).map(() => []),
+  )
+
+  const guessed = (a, b) => (lookup.has(a * 1_000_000 + b) ? 1 : 0)
+
+  const getCorrect = (node, parent) =>
+    adjList[node].reduce(
+      (total, child) =>
+        child === parent
+          ? total
+          : total + guessed(node, child) + getCorrect(child, node),
+      0,
+    )
+
+  const getTotal = (node, parent, correct) =>
+    (correct >= k ? 1 : 0) +
+    adjList[node].reduce(
+      (total, child) =>
+        child === parent
+          ? total
+          : total +
+            getTotal(
+              child,
+              node,
+              correct - guessed(node, child) + guessed(child, node),
+            ),
+      0,
+    )
+
+  return getTotal(0, -1, getCorrect(0, -1))
+}