adding challenges for hw

add-eventing/add-eventing.js

@@ -1,4 +1,18 @@
 const addEventing = function (obj) {
+    const addEventing = function (obj) {
+        let events = {}
+        obj.on = (eventName, fn) => {
+          if (events[eventName]) {
+            events[eventName].push(fn)
+          } else {
+            events[eventName] = [fn]
+          }
+        }
+        obj.trigger = (eventName, ...args) => {
+          events[eventName].forEach(fn => fn(...args))
+        }
+        return obj
+    }
 }
 
 module.exports = addEventing

babylonian-method/babylonian.js

@@ -1,4 +1,10 @@
-const squareRoot = (radicand) => {
+function squareRoot(radicand) {
+  for (let i = radicand; i >= 1; i--) {
+    if (i * i == radicand) {
+      radicand = i;
+      break;
+    }
+  }
   return radicand
 }
 

balanced-parens/balanced-parens.js

@@ -1,5 +1,59 @@
-const parensAreBalanced = (input) => {
-  return false
+const parensAreBalanced = (str) => {
+  ///////  Balanced Parentheses
+  const parensAreBalanced = (str) => {
+    let stack = [];
+    let map = {
+        '(': ')',
+        '[': ']',
+        '{': '}'
+    }
+    for (let i = 0; i < str.length; i++) {
+        if (str[i] === '(' || str[i] === '{' || str[i] === '[' ) {
+            stack.push(str[i]);
+        }
+        else {
+            let last = stack.pop();
+            if (str[i] !== map[last]) {
+                return false
+            };
+        }
+    }
+        if (stack.length !== 0) {
+            return false
+        };
+    return true;
+  };
+  console.log (parensAreBalanced("(){}"));
+  console.log (parensAreBalanced('{}'));
+
+
+
+
+
+
+
+  /*let stack = [];
+    let map = {
+        '(': ')',
+        '[': ']',
+        '{': '}'
+    }
+    for (let i = 0; i < str.length; i++) {
+        if (str[i] === '(' || str[i] === '{' || str[i] === '[' ) {
+            stack.push(str[i]);
+        }
+        else {
+            let last = stack.pop();
+            if (str[i] !== map[last]) {
+                return false
+            };
+        }
+    }
+        if (stack.length !== 0) {
+            return false
+        };
+    return true;
 }
 
 module.exports = parensAreBalanced
+*/

stack-machine-calculator/stack-machine-calculator.js

@@ -1,5 +1,29 @@
 const stackMachineCalculator = (instructions) => {
-  return instructions
+  let stack = [];
+  let num = instructions.split("");
+
+  for(let i = 0; i < num.length; i++) {
+    switch(num[i]) {
+      case "+" : 
+      stack.push(stack.pop() + stack.pop());
+      break;
+
+      case "-" : 
+      stack.push(stack.pop() - stack.pop());
+      break;
+
+      case "*" : 
+      stack.push(stack.pop() * stack.pop());
+      break;
+
+      case "/" : 
+      stack.push(stack.pop() / stack.pop());
+      break;
+
+      default: stack.push(parseInt(num[i]));
+    }
+  }
+  return stack.pop();
 }
 
-module.exports = stackMachineCalculator
+module.exports = stackMachineCalculator