Solution_mini_challenge-4

src/count-islands/index.js

@@ -1,3 +1,37 @@
-function countIslands(grid) {}
+function countIslands(grid) {
+  const locateIsland = (grid, x, y, checked) => {
+    if (x < 0 || x > grid.length - 1 || y < 0 || y > grid[x].length - 1) return;
+
+    if (checked[x][y] === true) return;
+
+    checked[x][y] = true;
+    if (grid[x][y] === 0) return;
+
+    // @traversing the 2D Array
+    locateIsland(grid, x - 1, y, checked);
+    locateIsland(grid, x + 1, y, checked);
+    locateIsland(grid, x, y - 1, checked);
+    locateIsland(grid, x, y + 1, checked);
+  };
+
+  // @creation of boolean 2D Array of equal size with grid
+  // to help keep track of the visited node
+  let checked = [];
+  let count = 0;
+  for (let i = 0; i < grid.length; i++) {
+    checked.push([]);
+  }
+
+  for (let x = 0; x < grid.length; x++) {
+    for (let y = 0; y < grid[x].length; y++) {
+      if (!checked[x][y] && grid[x][y] === 1) {
+        count++;
+        locateIsland(grid, x, y, checked);
+      }
+      checked[x][y] = true;
+    }
+  }
+  return count;
+}
 
 module.exports = countIslands;

src/count-islands/test.js

@@ -25,12 +25,10 @@ describe("Count Islands", () => {
 
   test("4x4 island", () => {
     const grid = [
-      [
-        [1, 1, 0, 0],
-        [0, 0, 1, 0],
-        [0, 0, 0, 1],
-        [0, 1, 0, 0],
-      ],
+      [1, 1, 0, 0],
+      [0, 0, 1, 0],
+      [0, 0, 0, 1],
+      [0, 1, 0, 0],
     ];
 
     expect(countIslands(grid)).toBe(4);

src/word-search/index.js

@@ -1,3 +1,47 @@
-function wordSearch(words, word) {}
+function wordSearch(words, word) {
+  const findLink = (words, x, y, checked, word_index) => {
+    if (x < 0 || x > words.length - 1 || y < 0 || y > words[x].length - 1)
+      return;
+
+    if (checked[x][y] === true) return;
+
+    if (words[x][y] !== word[word_index]) return;
+
+    checked[x][y] = true;
+
+    if (word_index === word.length - 1) {
+      return true;
+    }
+
+    // @traversing four possible directions (left, right, up, down)
+    if (
+      findLink(words, x - 1, y, checked, word_index + 1) ||
+      findLink(words, x + 1, y, checked, word_index + 1) ||
+      findLink(words, x, y - 1, checked, word_index + 1) ||
+      findLink(words, x, y + 1, checked, word_index + 1)
+    ) {
+      return true;
+    } else {
+      checked[x][y] = false;
+    }
+  };
+
+  // @boolean 2D Array of equal size with words
+  // to help keep track of the visited node
+  let checked = [];
+  for (let i = 0; i < words.length; i++) {
+    checked.push([]);
+  }
+
+  for (let x = 0; x < words.length; x++) {
+    for (let y = 0; y < words[x].length; y++) {
+      if (!checked[x][y] && words[x][y] === word[0]) {
+        if (findLink(words, x, y, checked, 0)) return true;
+      }
+    }
+  }
+
+  return false;
+}
 
 module.exports = wordSearch;

src/word-search/test.js

@@ -122,4 +122,28 @@ describe("Word Search", () => {
 
     expect(wordSearch(words, word)).toBe(true);
   });
+
+  test("You've got the word", () => {
+    const words = [
+      ["C", "A", "A"],
+      ["A", "A", "A"],
+      ["B", "C", "D"],
+    ];
+
+    const word = "AAB";
+
+    expect(wordSearch(words, word)).toBe(true);
+  });
+
+  test("Because you can See", () => {
+    const words = [
+      ["A", "B", "C", "E"],
+      ["S", "F", "C", "S"],
+      ["A", "D", "E", "E"],
+    ];
+
+    const word = "SEE";
+
+    expect(wordSearch(words, word)).toBe(true);
+  });
 });