add: leetcode 419 solution

leetcode/0419.Battleships-in-a-Board/419. Battleships in a Board.go

@@ -0,0 +1,21 @@
+package leetcode
+
+func countBattleships(board [][]byte) (ans int) {
+	if len(board) == 0 || len(board[0]) == 0 {
+		return 0
+	}
+	for i := range board {
+		for j := range board[i] {
+			if board[i][j] == 'X' {
+				if i > 0 && board[i-1][j] == 'X' {
+					continue
+				}
+				if j > 0 && board[i][j-1] == 'X' {
+					continue
+				}
+				ans++
+			}
+		}
+	}
+	return
+}