Added Swift solution for "1020. Number of Enclaves"

10/20/m1020.swift

@@ -0,0 +1,53 @@
+// Solved:
+// (M) Number of Enclaves
+// https://leetcode.com/problems/number-of-enclaves/
+
+class Solution {
+	typealias Coord = (x: Int, y: Int)
+
+	private func _processEnclave(_ grid: inout [[Int]], _ x: Int, _ y: Int) -> Int {
+		let xmax = grid.count - 1, ymax = grid[0].count - 1
+		var tile: [Coord] = [(x, y)]
+		var nEnclave = 0
+
+		grid[x][y] = 0
+		while !tile.isEmpty {
+			let c = tile.removeLast()
+			// If the tile is on bound, this is not an enclave
+			if c.x == 0 || c.y == 0 || c.x == xmax || c.y == ymax { nEnclave = -1 }
+			if nEnclave >= 0 { nEnclave += 1 }
+			if c.x > 0 && grid[c.x - 1][c.y] == 1 { grid[c.x - 1][c.y] = 0; tile.append((c.x - 1, c.y)) }
+			if c.y > 0 && grid[c.x][c.y - 1] == 1 { grid[c.x][c.y - 1] = 0; tile.append((c.x, c.y - 1)) }
+			if c.x < xmax && grid[c.x + 1][c.y] == 1 { grid[c.x + 1][c.y] = 0; tile.append((c.x + 1, c.y)) }
+			if c.y < ymax && grid[c.x][c.y + 1] == 1 { grid[c.x][c.y + 1] = 0; tile.append((c.x, c.y + 1)) }
+		}
+
+		return nEnclave > 0 ? nEnclave : 0
+	}
+
+	func numEnclaves(_ grid: [[Int]]) -> Int {
+		var g = grid
+		var res = 0
+
+		// Obvious case - no inner tiles at all
+		if g.count <= 2 || g[0].count <= 2 { return 0 }
+
+		for i in 1..<g.count - 1 {
+			for j in 1..<g[0].count - 1 {
+				if g[i][j] == 1 {
+					res += _processEnclave(&g, i, j)
+				}
+			}
+		}
+
+		return res
+	}
+}
+
+func _main() {
+	let x = Solution()
+	// Must be 3
+	print(x.numEnclaves([[0,0,0,0],[1,0,1,0],[0,1,1,0],[0,0,0,0]]))
+	// Must be 27
+	print(x.numEnclaves([[0,0,0,1,1,1,0,1,1,1,1,1,0,0,0],[1,1,1,1,0,0,0,1,1,0,0,0,1,1,1],[1,1,1,0,0,1,0,1,1,1,0,0,0,1,1],[1,1,0,1,0,1,1,0,0,0,1,1,0,1,0],[1,1,1,1,0,0,0,1,1,1,0,0,0,1,1],[1,0,1,1,0,0,1,1,1,1,1,1,0,0,0],[0,1,0,0,1,1,1,1,0,0,1,1,1,0,0],[0,0,1,0,0,0,0,1,1,0,0,1,0,0,0],[1,0,1,0,0,1,0,0,0,0,0,0,1,0,1],[1,1,1,0,1,0,1,0,1,1,1,0,0,1,0]]))
+}