Create 2608-shortest-cycle-in-a-graph.js

Author: everthis

2608-shortest-cycle-in-a-graph.js

@@ -0,0 +1,40 @@
+/**
+ * @param {number} n
+ * @param {number[][]} edges
+ * @return {number}
+ */
+const findShortestCycle = function(n, edges) {
+  let res = Infinity
+  const graph = new Map()
+  for(const [u, v] of edges) {
+    if(graph.get(u) == null) graph.set(u, [])
+    if(graph.get(v) == null) graph.set(v, [])
+    graph.get(u).push(v)
+    graph.get(v).push(u)
+  }
+  for(let i = 0; i < n; i++) {
+    bfs(i)
+  }
+  
+  if(res === Infinity) return -1
+  return res
+  
+  function bfs(src) {
+    const parent = Array(n), dis = Array(n).fill(Infinity)
+    let q = []
+    dis[src] = 0
+    q.push(src)
+    while(q.length) {
+      const node = q.shift()
+      for(const nxt of (graph.get(node) || [])) {
+        if(dis[nxt] === Infinity) {
+          dis[nxt] = dis[node] + 1
+          parent[nxt] = node
+          q.push(nxt)
+        } else if(parent[node] !== nxt && parent[nxt] !== node) {
+          res = Math.min(res, dis[nxt] + dis[node] + 1)          
+        }
+      }
+    }
+  }
+};