Create 1905-count-sub-islands.go

Accepted submission: _https://leetcode.com/submissions/detail/870821099/_

go/1905-count-sub-islands.go

@@ -0,0 +1,39 @@
+func countSubIslands(grid1 [][]int, grid2 [][]int) int {
+    ROWS, COLS := len(grid1), len(grid1[0])
+    visit := make(map[int]bool)
+
+    var dfs func(int, int) bool
+    dfs = func(r, c int) bool {
+        if (
+            r < 0 ||
+            c < 0 ||
+            r == ROWS ||
+            c == COLS ||
+            grid2[r][c] == 0 ||
+            visit[r*COLS + c]) {
+            return true
+        }
+
+        visit[r*COLS + c] = true
+        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
+    }
+
+    count := 0
+    for r := 0; r < ROWS; r++ {
+        for c := 0; c < COLS; c++ {
+            if grid2[r][c] != 0 && !visit[r*COLS + c] && dfs(r, c) {
+                count += 1
+            }
+        }
+    }
+    return count
+}