Create 1257-smallest-common-region.js

Author: everthis

1257-smallest-common-region.js

@@ -0,0 +1,40 @@
+/**
+ * @param {string[][]} regions
+ * @param {string} region1
+ * @param {string} region2
+ * @return {string}
+ */
+const findSmallestRegion = function (regions, region1, region2) {
+  const hash = {}
+  for(const arr of regions) {
+    const p = arr[0]
+    const size = arr.length
+    for(let i = 1; i < size; i++) {
+      const e = arr[i]
+      if(hash[e] == null) hash[e] = []
+      hash[e].push(p)
+    }
+  }
+
+  const path1 = [region1], path2 = [region2]
+  traverse(region1, path1)
+  traverse(region2, path2)
+
+  let i = path1.length - 1, j = path2.length - 1
+  while(i >= 0 && j >= 0) {
+    if(path1[i] !== path2[j]) break
+    else {
+      i--
+      j--
+    }
+  }
+
+  return path1[i + 1]
+
+  function traverse(node, res) {
+    if(hash[node] == null) return
+    res.push(hash[node][0])
+    traverse(hash[node][0], res)
+  }
+
+}