diff --git a/src/index.js b/src/index.js
index 4101a36..471dfab 100644
--- a/src/index.js
+++ b/src/index.js
@@ -4,7 +4,24 @@
  * @returns {number[][]}
  */
 const findNodesWithZeroAndOneParents = (parentChildPairs) => {
+  let totalParentsMap = new Map();
+  parentChildPairs.forEach((element) => {
+    if (!totalParentsMap.has(element[0])) {
+      totalParentsMap.set(element[0], 0);
+    }
+    let totalParent = totalParentsMap.get(element[1]) || 0;
+    totalParentsMap.set(element[1], ++totalParent);
+  });
+  let zeroParents = [];
+  let oneParent = [];
+  for (let [key, value] of totalParentsMap) {
+    if (value === 0) {
+      zeroParents.push(key);
+      continue;
+    }
+    if (value === 1) oneParent.push(key);
+  }
+  return [zeroParents, oneParent];
+};
 
-}
-
-module.exports = findNodesWithZeroAndOneParents;
\ No newline at end of file
+module.exports = findNodesWithZeroAndOneParents;