Add solution #419

Author: JoshCrozier

README.md

@@ -136,6 +136,7 @@
 383|[Ransom Note](./0383-ransom-note.js)|Easy|
 387|[First Unique Character in a String](./0387-first-unique-character-in-a-string.js)|Easy|
 414|[Third Maximum Number](./0414-third-maximum-number.js)|Easy|
+419|[Battleships in a Board](./0419-battleships-in-a-board.js)|Medium|
 442|[Find All Duplicates in an Array](./0442-find-all-duplicates-in-an-array.js)|Medium|
 448|[Find All Numbers Disappeared in an Array](./0448-find-all-numbers-disappeared-in-an-array.js)|Easy|
 451|[Sort Characters By Frequency](./0451-sort-characters-by-frequency.js)|Medium|

solutions/0419-battleships-in-a-board.js

@@ -0,0 +1,31 @@
+/**
+ * 419. Battleships in a Board
+ * https://leetcode.com/problems/battleships-in-a-board/
+ * Difficulty: Medium
+ *
+ * Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the
+ * number of the battleships on board.
+ *
+ * Battleships can only be placed horizontally or vertically on board. In other words, they
+ * can only be made of the shape 1 x k (1 row, k columns) or k x 1 (k rows, 1 column), where
+ * k can be of any size. At least one horizontal or vertical cell separates between two
+ * battleships (i.e., there are no adjacent battleships).
+ */
+
+/**
+ * @param {character[][]} boardx
+ * @return {number}
+ */
+var countBattleships = function(board) {
+  let count = 0;
+
+  for (let i = 0; i < board.length; i++) {
+    for (let j = 0; j < board[i].length; j++) {
+      if (board[i][j] === 'X' && board[i][j - 1] !== 'X' && (!board[i - 1] || board[i - 1][j] !== 'X')) {
+        count++;
+      }
+    }
+  }
+
+  return count;
+};