Create flood-fill.cpp

Author: kamyu104

C++/flood-fill.cpp

@@ -0,0 +1,27 @@
+// Time:  O(m * n)
+// Space: O(m * n)
+
+class Solution {
+public:
+    vector<vector<int>> floodFill(vector<vector<int>>& image, int sr, int sc, int newColor) {         
+        int color = image[sr][sc];
+        if (color == newColor) return image;
+        dfs(&image, sr, sc, newColor, color);
+        return image;
+    }
+
+private:
+    void dfs(vector<vector<int>> *image, int r, int c, int newColor, int color) {
+        static const vector<pair<int, int>> directions{{-1,  0}, { 1,  0},
+                                                       { 0,  1}, { 0, -1}};
+        if (r < 0 || r >= image->size() ||
+            c < 0 || c >= (*image)[0].size() ||
+            (*image)[r][c] != color) {
+            return;
+        }
+        (*image)[r][c] = newColor;
+        for (const auto& d : directions) {
+            dfs(image, r + d.first, c + d.second, newColor, color);
+        }
+    }
+};