Add JavaScript solution to the problem 1020.飞地的数量

Author: nicolasleigh

problems/1020.飞地的数量.md

@@ -605,6 +605,63 @@ func bfs(grid [][]int, i, j int) {
 }
 ```
 
+### JavaScript
+
+```js
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+var numEnclaves = function (grid) {
+  let row = grid.length;
+  let col = grid[0].length;
+  let count = 0;
+
+  // Check the first and last row, if there is a 1, then change all the connected 1s to 0 and don't count them.
+  for (let j = 0; j < col; j++) {
+    if (grid[0][j] === 1) {
+      dfs(0, j, false);
+    }
+    if (grid[row - 1][j] === 1) {
+      dfs(row - 1, j, false);
+    }
+  }
+
+  // Check the first and last column, if there is a 1, then change all the connected 1s to 0 and don't count them.
+  for (let i = 0; i < row; i++) {
+    if (grid[i][0] === 1) {
+      dfs(i, 0, false);
+    }
+    if (grid[i][col - 1] === 1) {
+      dfs(i, col - 1, false);
+    }
+  }
+
+  // Check the rest of the grid, if there is a 1, then change all the connected 1s to 0 and count them.
+  for (let i = 1; i < row - 1; i++) {
+    for (let j = 1; j < col - 1; j++) {
+      dfs(i, j, true);
+    }
+  }
+
+  function dfs(i, j, isCounting) {
+    let condition = i < 0 || i >= grid.length || j < 0 || j >= grid[0].length || grid[i][j] === 0;
+
+    if (condition) return;
+    if (isCounting) count++;
+
+    grid[i][j] = 0;
+
+    dfs(i - 1, j, isCounting);
+    dfs(i + 1, j, isCounting);
+    dfs(i, j - 1, isCounting);
+    dfs(i, j + 1, isCounting);
+  }
+
+  return count;
+};
+```
+
 ### Rust
 
 dfs:
@@ -700,3 +757,4 @@ impl Solution {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
+