Solved Week 2 assignments

week-2/week-2-async-js/easy/counter.js

@@ -0,0 +1,15 @@
+let count = 1;
+/* 
+setInterval(() => {
+  console.log(count);
+  count++;
+}, 1000);
+ */
+
+function counter() {
+  console.log(count);
+  count++;
+  setTimeout(counter, 1000);
+}
+
+counter();

week-2/week-2-async-js/hard (promises)/1-promisify-setTimeout.js

@@ -3,6 +3,9 @@
 */
 
 function wait(n) {
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, n * 1000);
+  });
 }
 
 module.exports = wait;

week-2/week-2-async-js/hard (promises)/2-sleep-completely.js

@@ -5,6 +5,11 @@
  */
 
 function sleep(milliseconds) {
+  return new Promise((resolve, reject) => {
+    const startTime = new Date().getTime();
+    while (new Date().getTime() < startTime + milliseconds);
+    resolve();
+  });
 }
 
 module.exports = sleep;

week-2/week-2-async-js/hard (promises)/3-promise-all.js

@@ -5,19 +5,29 @@
  */
 
 function wait1(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function wait2(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function wait3(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function calculateTime(t1, t2, t3) {
-
+  const startTime = Date.now();
+  return Promise.all([wait1(t1), wait2(t2), wait3(t3)]).then(() => {
+    const endTime = Date.now();
+    return endTime - startTime;
+  });
 }
 
 module.exports = calculateTime;

week-2/week-2-async-js/hard (promises)/4-promise-chain.js

@@ -6,19 +6,33 @@
  */
 
 function wait1(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function wait2(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function wait3(t) {
-
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, t * 1000);
+  });
 }
 
 function calculateTime(t1, t2, t3) {
-
+  const startTime = Date.now();
+
+  return wait1(t1)
+    .then(() => wait2(t2))
+    .then(() => wait3(t3))
+    .then(() => {
+      const endTime = Date.now();
+      return endTime - startTime;
+    });
 }
 
 module.exports = calculateTime;

week-2/week-2-js/easy/anagram.js

@@ -5,7 +5,11 @@
 */
 
 function isAnagram(str1, str2) {
+  function normalize(str) {
+    return str.toLowerCase().replace(/\s+/g, "").split("").sort().join("");
+  }
 
+  return normalize(str1) == normalize(str2);
 }
 
 module.exports = isAnagram;

week-2/week-2-js/easy/expenditure-analysis.js

@@ -14,7 +14,29 @@
 */
 
 function calculateTotalSpentByCategory(transactions) {
-  return [];
+  let result = [];
+
+  for (let i = 0; i < transactions.length; i++) {
+    var transaction = transactions[i];
+    var categoryExists = false;
+
+    for (let j = 0; j < result.length; j++) {
+      if (result[j].category == transaction.category) {
+        result[j].totalSpent += transaction.price;
+        categoryExists = true;
+        break;
+      }
+    }
+
+    if (!categoryExists) {
+      result.push({
+        category: transaction.category,
+        totalSpent: transaction.price,
+      });
+    }
+  }
+
+  return result;
 }
 
 module.exports = calculateTotalSpentByCategory;

week-2/week-2-js/easy/findLargestElement.js

@@ -6,7 +6,14 @@
 */
 
 function findLargestElement(numbers) {
-
+  let max = numbers[0];
+
+  for (let i = 1; i <= numbers.length; i++) {
+    if (max < numbers[i]) {
+      max = numbers[i];
+    }
+  }
+  return max;
 }
 
-module.exports = findLargestElement;
+module.exports = findLargestElement;

week-2/week-2-js/hard/calculator.js

@@ -16,6 +16,63 @@
   Once you've implemented the logic, test your code by running
 */
 
-class Calculator {}
+class Calculator {
+  constructor() {
+    this.result = 0;
+  }
+
+  add(num) {
+    this.result += num;
+    return this.result;
+  }
+
+  subtract(num) {
+    this.result -= num;
+    return this.result;
+  }
+
+  multiply(num) {
+    this.result *= num;
+    return this.result;
+  }
+
+  divide(num) {
+    if (num == 0) {
+      throw new Error("Cannot divide by zero");
+    }
+    this.result /= num;
+    return this.result;
+  }
+
+  clear() {
+    this.result = 0;
+    return this.result;
+  }
+
+  getResult() {
+    return this.result;
+  }
+
+  calculate(inputExpression) {
+    const expression = inputExpression.replace(/\s+/g, "");
+    const isValidExpression = /^[0-9+\-*/().]+$/.test(expression);
+
+    if (!isValidExpression) {
+      throw new Error("Invalid Expression");
+    }
+
+    try {
+      this.result = eval(expression);
+    } catch (error) {
+      throw new Error("Invalid Expression");
+    }
+
+    if (this.result == Infinity) {
+      throw new Error("Cannot divide a number by 0");
+    }
+
+    return this.result;
+  }
+}
 
 module.exports = Calculator;

week-2/week-2-js/hard/todo-list.js

@@ -11,7 +11,40 @@
 */
 
 class Todo {
+  constructor() {
+    this.todos = [];
+  }
 
+  add(todo) {
+    this.todos.push(todo);
+  }
+
+  remove(indexOfTodo) {
+    if (indexOfTodo >= 0 && indexOfTodo < this.todos.length) {
+      this.todos.splice(indexOfTodo, 1);
+    }
+  }
+
+  update(indexOfTodo, updatedTodo) {
+    if (indexOfTodo >= 0 && indexOfTodo < this.todos.length) {
+      this.todos[indexOfTodo] = updatedTodo;
+    }
+  }
+
+  getAll() {
+    return this.todos;
+  }
+
+  get(indexOfTodo) {
+    if (indexOfTodo >= 0 && indexOfTodo < this.todos.length) {
+      return this.todos[indexOfTodo];
+    }
+    return null;
+  }
+
+  clear() {
+    this.todos = [];
+  }
 }
 
 module.exports = Todo;

week-2/week-2-js/medium/countVowels.js

@@ -6,7 +6,19 @@
 */
 
 function countVowels(str) {
-    // Your code here
+  // Your code here
+  const vowels = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"];
+  let count = 0;
+
+  for (let i = 0; i < str.length; i++) {
+    for (let j = 0; j < vowels.length; j++) {
+      if (str[i] == vowels[j]) {
+        count++;
+      }
+    }
+  }
+
+  return count;
 }
 
-module.exports = countVowels;
+module.exports = countVowels;

week-2/week-2-js/medium/palindrome.js

@@ -4,6 +4,12 @@
 */
 
 function isPalindrome(str) {
+  let str1 = str.replace(/[\W_]/g, "").toLowerCase();
+  for (let i = 0; i < str1.length / 2; i++) {
+    if (str1[i] != str1[str1.length - i - 1]) {
+      return false;
+    }
+  }
   return true;
 }
 

week-2/week-2-js/medium/times.js

@@ -9,5 +9,17 @@ There is no automated test for this one, this is more for you to understand time
 */
 
 function calculateTime(n) {
-    return 0.01;
-}
+  const startTime = new Date().getTime();
+
+  let sum = 0;
+  for (let i = 1; i <= n; i++) {
+    sum += i;
+  }
+  const endTime = new Date().getTime();
+
+  return (endTime - startTime) / 1000;
+}
+
+console.log(calculateTime(100));
+console.log(calculateTime(100000));
+console.log(calculateTime(1000000000));