again changed path and added criticalConnections

Author: shkvik

src/bst/problems/bfs-all-paths.task.ts renamed to src/bst/bfs-all-paths.task.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 
 function maxPathSum(root: TreeNode | null): number {

src/bst/problems/bst-max-path-sum.ts renamed to src/bst/bst-max-path-sum.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function rightSideView(root: TreeNode | null): number[] {
   const result: number[] = [];

src/bst/problems/bst-side-view.ts renamed to src/bst/bst-side-view.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function deleteNode(root: TreeNode | null, key: number): TreeNode | null {
   if (!root) {

src/bst/problems/delete.ts renamed to src/bst/delete.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function findDuplicateSubtrees(root: TreeNode | null): TreeNode[] {
   const map = new Map<string, number>();

src/bst/problems/duplicates-subtrees.ts renamed to src/bst/duplicates-subtrees.ts

@@ -1,4 +1,4 @@
-import { TreeNode } from "../utilities";
+import { TreeNode } from "./utilities";
 
 function findMin(root: TreeNode | null): number | null {
   if (!root) {

src/bst/problems/find-min.ts renamed to src/bst/find-min.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function insertIntoBST(root: TreeNode | null, val: number): TreeNode | null {
   if (!root) {

src/bst/problems/insert.ts renamed to src/bst/insert.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function isBalanced(root: TreeNode | null): boolean {
   function checkBalance(node: TreeNode | null): number {

src/bst/problems/is-balanced.ts renamed to src/bst/is-balanced.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function isSymmetric(root: TreeNode | null): boolean {
   if (!root) return true;

src/bst/problems/is-symmetric.ts renamed to src/bst/is-symmetric.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function isValidBST(root: TreeNode | null, min?: number, max?: number): boolean {
   const currentVal = root?.val;

src/bst/problems/is-valid-bst.ts renamed to src/bst/is-valid-bst.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function lowestCommonAncestor(root: TreeNode | null, p: TreeNode | null, q: TreeNode | null): TreeNode | null {
   if (root === null || root === p || root === q) {

src/bst/problems/lowest-common-ancestor.ts renamed to src/bst/lowest-common-ancestor.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 export namespace Recursion {
   function maxDepth(root: TreeNode | null): number {

src/bst/problems/max-depth.ts renamed to src/bst/max-depth.ts

@@ -1,4 +1,4 @@
-import { printTree, TreeNode } from "../utilities";
+import { printTree, TreeNode } from "./utilities";
 
 function serialize(root: TreeNode): string {
   const preorderSerialize = (node: TreeNode) => {

src/bst/problems/serialize-and-deserialize.ts renamed to src/bst/serialize-and-deserialize.ts

@@ -0,0 +1,81 @@
+
+const connections = [
+  [0,1],
+  [1,2],
+  [2,0],
+  [1,3]
+]
+
+function criticalConnections(n: number, connections: number[][]): number[][] {
+  const graph: number[][] = Array.from({ length: n }, () => []);
+  const result: number[][] = [];
+  const disc: number[] = new Array(n).fill(-1); // Время открытия вершины
+  const low: number[] = new Array(n).fill(-1);  // Минимальное время посещения
+  let time = 0;
+
+  // Построение графа
+  for (const [u, v] of connections) {
+    graph[u].push(v);
+    graph[v].push(u);
+  }
+
+  // Основная функция DFS
+  const dfs = (u: number, parent: number) => {
+    disc[u] = low[u] = time++; // Инициализация времени открытия и low
+    for (const v of graph[u]) {
+      if (v === parent) continue; // Игнорируем родительскую вершину
+
+      if (disc[v] === -1) { // Если вершина v еще не посещена
+        dfs(v, u); // Рекурсивный DFS
+
+        // Обновляем low[u] на основе дочерней вершины v
+        low[u] = Math.min(low[u], low[v]);
+
+        // Если low[v] > disc[u], то (u, v) — критическое соединение
+        if (low[v] > disc[u]) {
+          result.push([u, v]);
+        }
+      } else {
+        // Обратное ребро, обновляем low[u]
+        low[u] = Math.min(low[u], disc[v]);
+      }
+    }
+  };
+
+  // Запуск DFS для всех вершин
+  for (let i = 0; i < n; i++) {
+    if (disc[i] === -1) {
+      dfs(i, -1); // -1 означает, что у начальной вершины нет родителя
+    }
+  }
+
+  return result;
+}
+
+
+export function criticalConnectionsDBG(){
+
+  const tests = [
+    {
+      input: { n: 4, connections: [[0, 1], [1, 2], [2, 0], [1, 3]] },
+      result: [[1, 3]] // Соединение [1, 3] является критическим
+    },
+    {
+      input: { n: 2, connections: [[0, 1]] },
+      result: [[0, 1]] // Единственное соединение [0, 1] является критическим
+    },
+  ];
+  
+  tests.forEach((test, index) => {
+    const result = criticalConnections(test.input.n, test.input.connections);
+    const success = JSON.stringify(result) === JSON.stringify(test.result);
+    if (success) {
+      console.log(`Test ${index} success`);
+    } else {
+      console.log(`Test ${index} fail`);
+      console.log(`expected: ${JSON.stringify(test.result)}`);
+      console.log(`got: ${JSON.stringify(result)}`);
+    }
+  });
+  
+}