finish 11

11-mean-median-mode.js

@@ -0,0 +1,41 @@
+function getMean(arr) {
+  return arr.reduce((sum, curr) => sum += curr, 0) / arr.length;
+}
+
+function getMedian(arr) {
+  arr.sort((a, b) => a > b);
+  if ((arr.length % 2) === 0) {
+    return (arr[arr.length / 2] + arr[arr.length / 2 - 1]) / 2
+  } else {
+    return arr[Math.floor(arr.length / 2)];
+  }
+}
+
+function getMode(arr) {
+  var obj = {};
+  var modes = [];
+  var maxCount = 0;
+  arr.forEach(e => {
+    obj[e] ? obj[e]++ : obj[e] = 1;
+    if (obj[e] > maxCount) {
+      modes = [e];
+      maxCount = obj[e];
+    }
+    if (obj[e] === maxCount && modes.indexOf(e) == -1) {
+      modes.push(e);
+    }
+  });
+  if (modes.length === Object.keys(obj).length) modes = [];
+  return modes;
+}
+
+function meanMedianMode(arr) {
+  return {
+    mean: getMean(arr),
+    median: getMedian(arr),
+    mode: getMode(arr)
+  }
+}
+
+
+console.log(meanMedianMode([1, 1, 3, 3, 4, 4, 5, 5, 6]))

README.md

@@ -17,6 +17,12 @@ When it comes to data stucture, people firstly think about python or Java which
 - 02 Recursion
 - 03 Binary Search Tree
 - 04 Hash Table
+- 05 Fizz Buzz
+- 06 Harmless Ransom Note
+- 07 Palindrome
+- 08 Caesar Cipher
+- 09 Eeverse Words
+- 10 Reverse Array In Place
 
 ## Author
 Andy Chen ([amazingandyyy](github.com/amazingandyyy))