Add 59_Spiral_Matrix_II.java

Matrix/59_Spiral_Matrix_II.java

@@ -0,0 +1,36 @@
+class Solution {
+    public int[][] generateMatrix(int n) {
+        int[][] res = new int[n][n];
+
+        int minCol = 0, maxCol = n - 1, minRow = 0, maxRow = n - 1;
+        int no = 1;
+
+        while (minCol <= maxCol && minRow <= maxRow) {
+            for (int i = minCol; i <= maxCol; i++) {
+                res[minRow][i] = no++;
+            }
+            ++minRow;
+
+            for (int i = minRow; i <= maxRow; i++) {
+                res[i][maxCol] = no++;
+            }
+            --maxCol;
+
+            if (minCol > maxCol || minRow > maxRow) {
+                break;
+            }
+
+            for (int i = maxCol; i >= minCol; i--) {
+                res[maxRow][i] = no++;
+            }
+            --maxRow;
+
+            for (int i = maxRow; i >= minRow; i--) {
+                res[i][minCol] = no++;
+            }
+            ++minCol;
+        }
+
+        return res;
+    }
+}