feat(cpp): add spiral_matrix.cpp

Author: ongshunping

cpp/Math and Geometry/spiral_matrix.cpp

@@ -0,0 +1,41 @@
+#include <vector>
+
+std::vector<int> spiralMatrix(std::vector<std::vector<int>>& matrix) {
+    if (matrix.empty()) {
+        return {};
+    }
+    std::vector<int> result;
+    // Initialize the matrix boundaries.
+    int top = 0, bottom = matrix.size() - 1;
+    int left = 0, right = matrix[0].size() - 1;
+    // Traverse the matrix in spiral order.
+    while (top <= bottom && left <= right) {
+        // Move from left to right along the top boundary.
+        for (int i = left; i <= right; i++) {
+            result.push_back(matrix[top][i]);
+        }
+        top++;
+        // Move from top to bottom along the right boundary.
+        for (int i = top; i <= bottom; i++) {
+            result.push_back(matrix[i][right]);
+        }
+        right--;
+        // Check that the bottom boundary hasn't passed the top boundary
+        // before moving from right to left along the bottom boundary.
+        if (top <= bottom) {
+            for (int i = right; i >= left; i--) {
+                result.push_back(matrix[bottom][i]);
+            }
+            bottom--;
+        }
+        // Check that the left boundary hasn't passed the right boundary
+        // before moving from bottom to top along the left boundary.
+        if (left <= right) {
+            for (int i = bottom; i >= top; i--) {
+                result.push_back(matrix[i][left]);
+            }
+            left++;
+        }
+    }
+    return result;
+}