Create 3459. Length of Longest V-Shaped Diagonal Segment (#869)

Author: Chayandas07

3459. Length of Longest V-Shaped Diagonal Segment

@@ -0,0 +1,62 @@
+class Solution {
+public:
+    int dr[4] = {-1, 1, 1, -1};
+    int dc[4] = {1, 1, -1, -1};
+
+    bool inBounds(int r, int c, int n, int m) {
+        return r >= 0 && r < n && c >= 0 && c < m;
+    }
+
+    int dfs(vector<vector<int>>& grid, int r, int c, int dir, bool canChange, int len, int searchFor) {
+        int n = grid.size();
+        int m = grid[0].size();
+        int maxi = len;
+        
+        if (dir != -1) {
+            int nr = r + dr[dir];
+            int nc = c + dc[dir];
+            if (inBounds(nr, nc, n, m) && grid[nr][nc] == searchFor) {
+                int nextVal = (searchFor == 2) ? 0 : 2;
+                maxi = max(maxi, dfs(grid, nr, nc, dir, canChange, len + 1, nextVal));
+            }
+        }
+
+        if (dir != -1 && canChange) {
+            int ndir = (dir + 1) % 4;
+            int nr = r + dr[ndir];
+            int nc = c + dc[ndir];
+            if (inBounds(nr, nc, n, m) && grid[nr][nc] == searchFor) {
+                int nextVal = (searchFor == 2) ? 0 : 2;
+                maxi = max(maxi, dfs(grid, nr, nc, ndir, false, len + 1, nextVal));
+            }
+        }
+
+        if (dir == -1) {
+            for (int i = 0; i < 4; i++) {
+                int nr = r + dr[i];
+                int nc = c + dc[i];
+                if (inBounds(nr, nc, n, m) && grid[nr][nc] == searchFor) {
+                    int nextVal = (searchFor == 2) ? 0 : 2;
+                    maxi = max(maxi, dfs(grid, nr, nc, i, canChange, len + 1, nextVal));
+                }
+            }
+        }
+
+        return maxi;
+    }
+
+    int lenOfVDiagonal(vector<vector<int>>& grid) {
+        int n = grid.size();
+        int m = grid[0].size();
+        int maxi = 0;
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                if (grid[i][j] == 1) {
+                    maxi = max(maxi, dfs(grid, i, j, -1, true, 1, 2));
+                }
+            }
+        }
+        return maxi;
+    }
+};