add 3243

Author: fishercoder1534

Diff for: paginated_contents/algorithms/4th_thousand/README.md

@@ -1,5 +1,6 @@
 | #    | Title                                                                                                                                                               | Solutions                                                                                                                         | Video                                                                         | Difficulty | Tag                                                                  
 |------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------|------------|----------------------------------------------------------------------
+| 3243 | [Shortest Distance After Road Addition Queries I](https://leetcode.com/problems/shortest-distance-after-road-addition-queries-i/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3243.java) |                                                                               | Medium     |
 | 3241 | [Time Taken to Mark All Nodes](https://leetcode.com/problems/time-taken-to-mark-all-nodes/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3241.java) |                                                                               | Hard       |
 | 3240 | [Minimum Number of Flips to Make Binary Grid Palindromic II](https://leetcode.com/problems/minimum-number-of-flips-to-make-binary-grid-palindromic-ii/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3240.java) |                                                                               | Medium     |
 | 3239 | [Minimum Number of Flips to Make Binary Grid Palindromic I](https://leetcode.com/problems/minimum-number-of-flips-to-make-binary-grid-palindromic-i/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3239.java) |                                                                               | Easy       |

Diff for: src/main/java/com/fishercoder/solutions/fourththousand/_3243.java

@@ -0,0 +1,45 @@
+package com.fishercoder.solutions.fourththousand;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+public class _3243 {
+    public static class Solution1 {
+        public int[] shortestDistanceAfterQueries(int n, int[][] queries) {
+            List<Integer>[] graph = new ArrayList[n];
+            for (int i = 0; i < n; i++) {
+                graph[i] = new ArrayList<>();
+                if (i + 1 < n) {
+                    graph[i].add(i + 1);
+                }
+            }
+            int[] ans = new int[queries.length];
+            for (int i = 0; i < queries.length; i++) {
+                graph[queries[i][0]].add(queries[i][1]);
+                ans[i] = bfs(graph, n)[n - 1];
+            }
+            return ans;
+        }
+
+        private int[] bfs(List<Integer>[] graph, int n) {
+            int[] shortest = new int[n];
+            Arrays.fill(shortest, -1);
+            shortest[0] = 0;
+            Queue<Integer> q = new LinkedList<>();
+            q.offer(0);
+            while (!q.isEmpty()) {
+                int curr = q.poll();
+                for (int next : graph[curr]) {
+                    if (shortest[next] == -1) {
+                        shortest[next] = shortest[curr] + 1;
+                        q.offer(next);
+                    }
+                }
+            }
+            return shortest;
+        }
+    }
+}

Diff for: src/test/java/com/fishercoder/fourththousand/_3243Test.java

@@ -0,0 +1,23 @@
+package com.fishercoder.fourththousand;
+
+import com.fishercoder.common.utils.CommonUtils;
+import com.fishercoder.solutions.fourththousand._3243;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+public class _3243Test {
+    private static _3243.Solution1 solution1;
+
+    @BeforeEach
+    public void setup() {
+        solution1 = new _3243.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertArrayEquals(new int[]{3, 2, 1}, solution1.shortestDistanceAfterQueries(5,
+                CommonUtils.convertLeetCodeIrregularLengths2DArrayInputIntoJavaArray("[2,4],[0,2],[0,4]")));
+    }
+}