From 835763fe6a2a98169a303572f01c3426704202d1 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Thu, 8 Aug 2024 11:11:50 +0200
Subject: [PATCH] =?UTF-8?q?java:=20add=20=C2=AB885.=20Spiral=20Matrix=20II?=
 =?UTF-8?q?I=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 java/spiral-matrix-iii.java | 41 +++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 java/spiral-matrix-iii.java

diff --git a/java/spiral-matrix-iii.java b/java/spiral-matrix-iii.java
new file mode 100644
index 0000000..34b87a4
--- /dev/null
+++ b/java/spiral-matrix-iii.java
@@ -0,0 +1,41 @@
+class Solution {
+  private record Coord(int x, int y) {
+    public void assign(int[] coord) {
+      coord[0] = y;
+      coord[1] = x;
+    }
+
+    public Coord add(Coord rhs) {
+      return new Coord(x + rhs.x, y + rhs.y);
+    }
+  }
+
+  private static final List<Coord> DIRECTIONS =
+      Arrays.asList(new Coord(1, 0), new Coord(0, 1), new Coord(-1, 0), new Coord(0, -1));
+
+  private boolean inBounds(int rows, int cols, Coord pos) {
+    return pos.y() >= 0 && pos.y() < rows && pos.x() >= 0 && pos.x() < cols;
+  }
+
+  public int[][] spiralMatrixIII(int rows, int cols, int rStart, int cStart) {
+    int[][] matrix = new int[rows * cols][2];
+
+    var pos = new Coord(cStart, rStart);
+    for (int i = 0, step = 1, direction = 0; i < matrix.length; ++step) {
+      for (int j = 0; j < 2; ++j) {
+        for (int k = 0; k < step; ++k) {
+          if (inBounds(rows, cols, pos)) {
+            pos.assign(matrix[i]);
+            ++i;
+          }
+
+          pos = pos.add(DIRECTIONS.get(direction));
+        }
+
+        direction = (direction + 1) % 4;
+      }
+    }
+
+    return matrix;
+  }
+}