Create 1905-count-sub-islands.cpp

Author: AP-Repositories

cpp/1905-count-sub-islands.cpp

@@ -0,0 +1,37 @@
+class Solution {
+public:
+    int countSubIslands(vector<vector<int>>& grid1, vector<vector<int>>& grid2) {
+        const int ROWS = grid1.size(), COLS = grid1[0].size();
+        set<int> visit;
+        
+        function<bool(int, int)> dfs = [&] (int r, int c) -> bool {
+            if (
+                r < 0
+                || c < 0
+                || r == ROWS
+                || c == COLS
+                || grid2[r][c] == 0
+                || visit.count(r*COLS + c)
+            )
+                return true;
+            
+            visit.insert(r*COLS + c);
+            bool res = true;
+            if(grid1[r][c] == 0)
+                res = false;
+            
+            res = dfs(r - 1, c) && res;
+            res = dfs(r + 1, c) && res;
+            res = dfs(r, c - 1) && res;
+            res = dfs(r, c + 1) && res;
+            return res;
+        };
+        
+        int count = 0;
+        for(int r = 0; r < ROWS; r++)
+            for(int c = 0; c < COLS; c++)
+                if(grid2[r][c] && !visit.count(r*COLS + c) && dfs(r, c))
+                    count += 1;
+        return count;
+    }
+};