Data Structures: Breadth-First Search

Data Structures/bfs.js

@@ -0,0 +1,34 @@
+// https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/breadth-first-search
+
+function bfs(graph, root) {
+  const nodesLen = {};
+  const n_nodes = graph[root].length;
+  for (let dst = 0; dst < n_nodes; dst++) {
+    nodesLen[dst] = Infinity;
+  }
+  nodesLen[root] = 0;
+  for (let q = [root], d = 1; ; d++) {
+    const newQ = [];
+    for (let src of q) {
+      for (let dst = 0; dst < n_nodes; dst++) {
+        if (nodesLen[dst] > d && graph[src][dst] > 0) {
+          nodesLen[dst] = d;
+          newQ.push(dst);
+        }
+      }
+    }
+    if (newQ.length <= 0) {
+      break;
+    }
+    q = newQ;
+  }
+  return nodesLen;
+}
+
+var exBFSGraph = [
+  [0, 1, 0, 0],
+  [1, 0, 1, 0],
+  [0, 1, 0, 1],
+  [0, 0, 1, 0],
+];
+console.log(bfs(exBFSGraph, 3));