| # | 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|

| 3242|[Design Neighbor Sum Service](https://leetcode.com/problems/design-neighbor-sum-service/)|[Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3242.java)|| Easy|

| 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.HashMap;

importjava.util.Map;

publicclass_3242 {

publicstaticclassSolution1 {

classneighborSum {

int[][]matrix;

intm;

intn;

Map<Integer,int[]>map;

publicneighborSum(int[][]grid) {

this.matrix =grid;

this.m =grid.length;

this.n =grid[0].length;

this.map =newHashMap<>();

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

for (intj =0;j <n;j++) {

map.put(grid[i][j],newint[]{i,j});

}

}

}

publicintadjacentSum(intvalue) {

int[]dirs =newint[]{0,1,0, -1,0};

int[]pos =this.map.get(value);

intsum =0;

for (inti =0;i <dirs.length -1;i++) {

intnextx =pos[0] +dirs[i];

intnexty =pos[1] +dirs[i +1];

if (nextx >=0 &&nextx <m &&nexty >=0 &&nexty <n) {

sum +=matrix[nextx][nexty];

}

}

returnsum;

}

publicintdiagonalSum(intvalue) {

int[][]dirs =newint[][]{

{-1,1},

{1,1},

{1, -1},

{-1, -1}

};

int[]pos =this.map.get(value);

intsum =0;

for (int[]dir :dirs) {

intnextx =pos[0] +dir[0];

intnexty =pos[1] +dir[1];

if (nextx >=0 &&nextx <m &&nexty >=0 &&nexty <n) {

sum +=matrix[nextx][nexty];

}

}

returnsum;

}

}

}

}