Update 1617-count-subtrees-with-max-distance-between-cities.js

Author: everthis

1617-count-subtrees-with-max-distance-between-cities.js

@@ -49,3 +49,70 @@ const countSubgraphsForEachDiameter = function (n, edges) {
     return ans;
   }
 };
+
+// another
+
+/**
+ * @param {number} n
+ * @param {number[][]} edges
+ * @return {number[]}
+ */
+const countSubgraphsForEachDiameter = function(n, edges) {
+  const graph = {}
+  for(const [u, v] of edges) {
+    if(graph[u - 1] == null) graph[u - 1] = []
+    if(graph[v - 1] == null) graph[v - 1] = []
+    graph[u - 1].push(v - 1)
+    graph[v - 1].push(u - 1)
+  }
+  const res = Array(n - 1).fill(0)
+  
+  for(let i = 0, len = 2 ** n; i < len; i++) {
+    const dis = maxDistance(i)
+    if(dis > 0) res[dis - 1]++
+  }
+  
+  return res
+  
+  function bfs(src, cities) {
+    const visited = new Set([src])
+    let q = [[src, 0]]
+    let maxDist = 0
+    while(q.length) {
+      const tmp = []
+      const size = q.length
+      for(let i = 0; i < size; i++) {
+        const [u, d] = q[i]
+        maxDist = d
+        for(const v of (graph[u] || [])) {
+          if(cities.has(v) && !visited.has(v)) {
+            visited.add(v)
+            tmp.push([v, d + 1])
+          }
+        }
+      }
+      
+      q = tmp
+    }
+    
+    return [maxDist, visited]
+  }
+  
+  function maxDistance(state) {
+    const cities = new Set()
+    for(let i = 0; i < n; i++) {
+      if(state & (1 << i)) cities.add(i)
+    }
+    
+    let res = 0
+    for(const e of cities) {
+      const [maxDist, visited] = bfs(e, cities)
+      if(visited.size < cities.size) return 0
+      res = Math.max(res, maxDist) 
+    }
+    
+    return res
+  }
+}; 
+
+