Merge pull request #97 from vanditkhurana1/patch-1

Committing SpiralMatrix.java

Author: jvm-coder

SpiralMatrix.java

@@ -0,0 +1,51 @@
+
+import java.util.*;
+
+class SpiralMatrix{
+
+	// 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));
+	}
+}