Create 1020-number-of-enclaves.kt

kotlin/1020-number-of-enclaves.kt

@@ -0,0 +1,52 @@
+class Solution {
+ fun numEnclaves(grid: Array<IntArray>): Int {
+ val rows = grid.size
+ val cols = grid[0].size
+ val dirs = arrayOf(
+ intArrayOf(1, 0),
+ intArrayOf(-1, 0),
+ intArrayOf(0, 1),
+ intArrayOf(0, -1)
+ )
+
+ val visited = Array(rows){BooleanArray(cols)}
+
+ fun isValid(r: Int, c: Int) = 
+ r in (0 until rows) && 
+ c in (0 until cols) && 
+ visited[r][c] == false && 
+ grid[r][c] == 1
+
+ fun isValidBorder(r: Int, c: Int) = 
+ (r == 0 || r == rows - 1 || c == 0 || c == cols - 1) && 
+ visited[r][c] == false
+
+ fun dfs(r: Int, c: Int): Int {
+ if (!isValid(r, c))
+ return 0
+
+ visited[r][c] = true
+
+ var res = 1
+ for ((dr, dc) in dirs) {
+ res += dfs(r + dr, c + dc)
+ }
+
+ return res
+ }
+
+ var totalLand = 0
+ var borderLand = 0
+ for (r in 0 until rows) {
+ for (c in 0 until cols) {
+ totalLand += grid[r][c]
+ if (grid[r][c] == 1 && isValidBorder(r, c)) {
+ borderLand += dfs(r, c)
+ }
+ }
+ }
+
+ return totalLand - borderLand
+ }
+
+}