marking correct candidates

new_lineage_panel/src/graph.ts

@@ -298,8 +298,54 @@ export const markLastSecondNode = (
   }
 
   console.log("dfsTraversal:result:", right, nodeHeights);
-  return Object.entries(nodeHeights)
+  const lastSecondLeafNodes = Object.entries(nodeHeights)
     .filter(([, v]) => v === 2).map(([k]) => k);
+  const calculateAncestors = (lastSecondLeafNodes: string[]) => {
+    const ancestors: Record<string, string[]> = {};
+    const visited: Record<string, boolean> = {};
+    for (const n of lastSecondLeafNodes) ancestors[n] = [];
+    for (const candidate of lastSecondLeafNodes) {
+      const queue = [candidate];
+      while (queue.length > 0) {
+        const curr = queue.shift()!;
+        if (visited[curr]) continue; // maybe cycle, should ignore candidate??
+        visited[curr] = true;
+        for (const e of prevEdges) {
+          if (isColumn(e)) continue;
+          if (e[src] !== curr) continue;
+          const target = e[dst];
+          ancestors[target] = ancestors[target] || [];
+          ancestors[target].push(curr);
+          ancestors[target].push(...(ancestors[curr] || []));
+          queue.push(target);
+        }
+      }
+    }
+    return ancestors;
+  };
+  const calculateCandidates = (
+    lastSecondLeafNodes: string[],
+    ancestors: Record<string, string[]>,
+  ) => {
+    const potentialCandidates: Record<string, boolean> = {};
+    for (const n of lastSecondLeafNodes) potentialCandidates[n] = true;
+    for (const k in ancestors) {
+      if (lastSecondLeafNodes.includes(k)) continue;
+      let count = 0;
+      for (const a of ancestors[k]) {
+        if (lastSecondLeafNodes.includes(a)) count++;
+        if (count > 1) {
+          for (const v of ancestors[k]) potentialCandidates[v] = false;
+        }
+      }
+    }
+    return Object.entries(potentialCandidates).filter(([, v]) => v).map((
+      [k],
+    ) => k);
+  };
+  const ancestors = calculateAncestors(lastSecondLeafNodes);
+  const candidates = calculateCandidates(lastSecondLeafNodes, ancestors);
+  return candidates;
 };
 
 export const processColumnLineage = async (