feat: spiral-matrix

Author: minji-go

spiral-matrix/minji-go.java

@@ -0,0 +1,39 @@
+/**
+ * <a href="https://leetcode.com/problems/spiral-matrix/">week06-5.spiral-matrix</a>
+ * <li>Description: return all elements of the matrix in spiral order</li>
+ * <li>Topics: Array, Matrix, Simulation        </li>
+ * <li>Time Complexity: O(N*M), Runtime 0ms     </li>
+ * <li>Space Complexity: O(1), Memory 41.95MB   </li>
+ */
+class Solution {
+    public List<Integer> spiralOrder(int[][] matrix) {
+        List<Integer> answer = new ArrayList<>();
+        int lr = 0;
+        int hr = matrix.length-1;
+        int lc = 0;
+        int hc = matrix[0].length-1;
+
+        while (lr<=hr && lc<=hc) {
+            for(int c=lc; c<=hc && lr<=hr; c++) {
+                answer.add(matrix[lr][c]);
+            }
+            lr++;
+
+            for(int r=lr; r<=hr && lc<=hc; r++) {
+                answer.add(matrix[r][hc]);
+            }
+            hc--;
+
+            for(int c=hc; c>=lc && lr<=hr; c--){
+                answer.add(matrix[hr][c]);
+            }
+            hr--;
+
+            for(int r=hr; r>=lr && lc<=hc; r--){
+                answer.add(matrix[r][lc]);
+            }
+            lc++;
+        }
+        return answer;
+    }
+}