From 1cc7fd0b13aa5cc84c0600fef60f3864311d7d88 Mon Sep 17 00:00:00 2001
From: Fahim Abbasi <63852008+fahamabbasi@users.noreply.github.com>
Date: Fri, 15 Oct 2021 16:46:08 +0700
Subject: [PATCH] Create SpiralMatrix.java

Input:  1    2   3   4
        5    6   7   8
        9   10  11  12
        13  14  15  16
Output: 1 2 3 4 8 12 16 15 14 13 9 5 6 7 11 10
Explanation: The output is matrix in spiral format.

Input:  1   2   3   4  5   6
        7   8   9  10  11  12
        13  14  15 16  17  18
Output: 1 2 3 4 5 6 12 18 17 16 15 14 13 7 8 9 10 11
Explanation :The output is matrix in spiral format.
---
 SpiralMatrix.java | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 SpiralMatrix.java

diff --git a/SpiralMatrix.java b/SpiralMatrix.java
new file mode 100644
index 0000000..44693b1
--- /dev/null
+++ b/SpiralMatrix.java
@@ -0,0 +1,50 @@
+import java.util.*;
+ 
+class Solution {
+ 
+    // Function to print in spiral order
+    public static List<Integer> spiralOrder(int[][] matrix)
+    {
+        List<Integer> ans = new ArrayList<Integer>();
+ 
+        if (matrix.length == 0)
+            return ans;
+ 
+        int R = matrix.length, C = matrix[0].length;
+        boolean[][] seen = new boolean[R][C];
+        int[] dr = { 0, 1, 0, -1 };
+        int[] dc = { 1, 0, -1, 0 };
+        int r = 0, c = 0, di = 0;
+ 
+        // Iterate from 0 to R * C - 1
+        for (int i = 0; i < R * C; i++) {
+            ans.add(matrix[r]);
+            seen[r] = true;
+            int cr = r + dr[di];
+            int cc = c + dc[di];
+ 
+            if (0 <= cr && cr < R && 0 <= cc && cc < C
+                && !seen[cr][cc]) {
+                r = cr;
+                c = cc;
+            }
+            else {
+                di = (di + 1) % 4;
+                r += dr[di];
+                c += dc[di];
+            }
+        }
+        return ans;
+    }
+ 
+    // Driver Code
+    public static void main(String[] args)
+    {
+        int a[][] = { { 1, 2, 3, 4 },
+                      { 5, 6, 7, 8 },
+                      { 9, 10, 11, 12 },
+                      { 13, 14, 15, 16 } };
+ 
+        System.out.println(spiralOrder(a));
+    }
+}