Create 959. Regions Cut By Slashes (#553)

959. Regions Cut By Slashes

@@ -0,0 +1,46 @@
+class Solution {
+private:
+    vector<pair<int, int>> dirs = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
+    unordered_map<char, vector<vector<int>>> mp = {
+        {'/', {{0, 0, 1}, {0, 1, 0}, {1, 0, 0}}},
+        {'\\', {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}},
+        {' ', {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}}
+    };
+    vector<vector<int>> zoom(vector<string>& grid){
+        int n = grid.size();
+        vector<vector<int>> res(3*n, vector<int>(3*n, 0));
+        for(int i = 0; i < n; i++){
+            for(int j = 0; j < n; j++){
+                for(int r = 0; r < 3; r++){
+                    for(int c = 0; c < 3; c++){
+                        res[3*i+r][3*j+c] = mp[grid[i][j]][r][c]; 
+                    }
+                }
+            }
+        }
+        return res;
+    }
+    void markRegion(vector<vector<int>>& grid, int r, int c){
+        if(grid[r][c] == -1 || grid[r][c] == 1) return;
+        grid[r][c] = -1;
+        int n = grid.size();
+        for(auto& [x, y]: dirs){
+            int new_x = r + x, new_y = c + y;
+            if(new_x >= 0 && new_y >= 0 && new_x < n && new_y < n) markRegion(grid, new_x, new_y);
+        }
+    }
+public:
+    int regionsBySlashes(vector<string>& grid) {
+        int cnt = 0;
+        vector<vector<int>> zoomed = zoom(grid);
+        int n = zoomed.size();
+        for(int i = 0; i < n; i++){
+            for(int j = 0; j < n; j++){
+                if(zoomed[i][j] == -1 || zoomed[i][j] == 1) continue;
+                cnt++;
+                markRegion(zoomed, i, j);
+            }
+        }
+        return cnt;
+    }
+};