Spiral Matrix

Author: TonyKim9401

spiral-matrix/TonyKim9401.java

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+class Solution {
+    public List<Integer> spiralOrder(int[][] matrix) {
+        List<Integer> output = new ArrayList<>();
+        int north = 0;
+        int south = matrix.length - 1;
+        int east = matrix[0].length - 1;
+        int west = 0;
+
+        while (north <= south && west <= east) {
+            int j = west;
+            while (j <= east) {
+                output.add(matrix[north][j]);
+                j += 1;
+            }
+            north += 1;
+
+            int i = north;
+            while (i <= south) {
+                output.add(matrix[i][east]);
+                i += 1;
+            }
+            east -= 1;
+
+            if (north <= south) {
+                j = east;
+                while (j >= west) {
+                    output.add(matrix[south][j]);
+                    j -= 1;
+                }
+                south -= 1;
+            }
+
+            if (west <= east) {
+                i = south;
+                while (i >= north) {
+                    output.add(matrix[i][west]);
+                    i -= 1;
+                }
+                west += 1;
+            }
+        }
+        return output;
+    }
+}