updated challenge 4

src/count-islands/index.js

@@ -1,3 +1,30 @@
-function countIslands(grid) {}
+const wordSearch = require("../word-search");
 
+function countIslands(grid) {
+
+    var count = 0;
+	let n = grid.length;
+	if (n == 0) return 0;
+	let m = grid[0].length;
+
+	for (let i = 0; i < n; i++) {
+		for (let j = 0; j < m; j++)
+			if (grid[i][j] == '1') {
+				DFS(grid, i, j);
+				++count;
+			}
+	}
+    return count;};
+
+    function DFS(grid, row, col) {
+    if (row < 0 || col < 0 || row >= grid.length || col >= grid[0].length || grid[row][col] != '1') return;
+	grid[row][col] = '0';
+	DFS(grid, row + 1, col);
+	DFS(grid, row - 1, col);
+	DFS(grid, row, col + 1);
+	DFS(grid, row, col - 1);
+}
+
+
+
 module.exports = countIslands;

src/word-search/index.js

@@ -1,3 +1,33 @@
-function wordSearch(words, word) {}
+function wordSearch(words, word) {
+
+    if(word ===" ") return true;
+    for(let row = 0;row < words.length; row++){
+        for(let col = 0; col < words[row].length; col++){
+            if(words[row][col] === word[0]){
+                if(search(0, row, col))
+                return true;
+            }
+        }
+    }
+    return false;
+
+    function search(index, x, y){
+        if(index === word.length) return true;
+        if(!words[x] || !words[x][y]) return false;
+
+        if(words[x][y] !== '#' && words[x][y] === word[index]){
+            let letter = words[x][y];
+            words[x][y] = '#';
+
+            if(search(index+1, x - 1, y)) return true;
+            if(search(index+1, x + 1, y)) return true;
+            if(search(index+1, x , y - 1)) return true;
+            if(search(index+1, x , y + 1)) return true;
+
+            words[x][y] = letter;
+        }
+        return false;
+    }
+}
 
 module.exports = wordSearch;