204th Commit

README.md

@@ -204,11 +204,12 @@ Ace Coding Interview with 75 Qs
 | Graphs - DFS                                                 |                 |        |
 | ------------------------------------------------------------ | --------------- | ------ |
 | 841. Keys and Rooms                                          | [Solution][841] | Medium |
-| 547. Number of Provinces                                     | Solution        | Medium |
+| 547. Number of Provinces                                     | [Solution][547] | Medium |
 | 1466. Reorder Routes to Make All Paths Lead to the City Zero | Solution        | Medium |
 | 399. Evaluate Division                                       | Solution        | Medium |
 
 [841]: ./src/page-8/841.%20Keys%20and%20Rooms/canVisitAllRooms.ts
+[547]: ./src/page-6/547.%20Number%20of%20Provinces/findCircleNum.ts
 
 | Graphs - BFS                             |          |        |
 | ---------------------------------------- | -------- | ------ |

src/page-6/547. Number of Provinces/findCircleNum.test.ts

@@ -0,0 +1,21 @@
+import { findCircleNum } from './findCircleNum';
+
+describe('547. Number of Provinces', () => {
+  test('findCircleNum', () => {
+    expect(
+      findCircleNum([
+        [1, 1, 0],
+        [1, 1, 0],
+        [0, 0, 1],
+      ]),
+    ).toBe(2);
+
+    expect(
+      findCircleNum([
+        [1, 0, 0],
+        [0, 1, 0],
+        [0, 0, 1],
+      ]),
+    ).toBe(3);
+  });
+});

src/page-6/547. Number of Provinces/findCircleNum.ts

@@ -0,0 +1,35 @@
+type FindCircleNum = (isConnected: number[][]) => number;
+
+/**
+ * Accepted
+ */
+export const findCircleNum: FindCircleNum = (isConnected) => {
+  const n = isConnected.length; // Number of cities (or nodes in the graph)
+  const visited = Array(n).fill(false); // Array to keep track of visited cities
+
+  // DFS function to explore all cities in the current province
+  const dfs = (i: number) => {
+    // Traverse all cities
+    for (let j = 0; j < n; j++) {
+      // If city 'i' is directly connected to city 'j' and 'j' has not been visited yet
+      if (isConnected[i][j] === 1 && !visited[j]) {
+        visited[j] = true; // Mark city 'j' as visited
+        dfs(j); // Recursively visit all cities connected to city 'j'
+      }
+    }
+  };
+
+  let provinces = 0; // Variable to count the number of provinces
+
+  // Loop through each city
+  for (let i = 0; i < n; i++) {
+    // If the city hasn't been visited yet, it's a new province
+    if (!visited[i]) {
+      provinces += 1; // Increment the province count
+      visited[i] = true; // Mark the current city as visited
+      dfs(i); // Perform DFS to visit all cities in this province
+    }
+  }
+
+  return provinces; // Return the total number of provinces found
+};