| # | 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|

packagecom.fishercoder.solutions.fourththousand;

importjava.util.ArrayList;

importjava.util.Arrays;

importjava.util.LinkedList;

importjava.util.List;

importjava.util.Queue;

publicclass_3243 {

publicstaticclassSolution1 {

publicint[]shortestDistanceAfterQueries(intn,int[][]queries) {

List<Integer>[]graph =newArrayList[n];

for (inti =0;i <n;i++) {

graph[i] =newArrayList<>();

if (i +1 <n) {

graph[i].add(i +1);

}

}

int[]ans =newint[queries.length];

for (inti =0;i <queries.length;i++) {

graph[queries[i][0]].add(queries[i][1]);

ans[i] =bfs(graph,n)[n -1];

}

returnans;

}

privateint[]bfs(List<Integer>[]graph,intn) {

int[]shortest =newint[n];

Arrays.fill(shortest, -1);

shortest[0] =0;

Queue<Integer>q =newLinkedList<>();

q.offer(0);

while (!q.isEmpty()) {

intcurr =q.poll();

for (intnext :graph[curr]) {

if (shortest[next] == -1) {

shortest[next] =shortest[curr] +1;

q.offer(next);

}

}

}

returnshortest;

}

}

}

packagecom.fishercoder.fourththousand;

importcom.fishercoder.common.utils.CommonUtils;

importcom.fishercoder.solutions.fourththousand._3243;

importorg.junit.jupiter.api.BeforeEach;

importorg.junit.jupiter.api.Test;

importstaticorg.junit.jupiter.api.Assertions.assertArrayEquals;

publicclass_3243Test {

privatestatic_3243.Solution1solution1;

publicvoidsetup() {

solution1 =new_3243.Solution1();

}

publicvoidtest1() {

assertArrayEquals(newint[]{3,2,1},solution1.shortestDistanceAfterQueries(5,

CommonUtils.convertLeetCodeIrregularLengths2DArrayInputIntoJavaArray("[2,4],[0,2],[0,4]")));

}

}