finished chapter 8

bucket sort - non-linked-list version

Author: Shoya90

Utils.js

@@ -27,6 +27,18 @@ util.randomArrayWithNegatives = (to) => {
     return A
 }
 
+util.randomArrayBetween0And1 = (n) => {
+    A = []
+    for (let i = 0; i < n; i++) {
+        let num = Math.random()
+        while(num == 1){
+            num = Math.random()
+        }
+        A.push(num)
+    }
+    return A
+}
+
 util.AlgorithmInfoLog = (algorithm, A, print_array = true, print_time = true, print_memory = true) => {
     print_array && console.log(chalk.blue([A[0]]))
     print_time && console.time(algorithm.name)

ch_2/insertion_sort.js

@@ -3,7 +3,7 @@ insertion_sort = (A) => {
         key = A[j]
         // insert A[j] into the sorted sub sequence A[0,...,j-1]
         i = j - 1
-        while(i >= 0 && A[i] < key){
+        while(i >= 0 && A[i] > key){
             // copy each element to its right position
             A[i + 1] = A[i]
             i -= 1

ch_8/Problems/Problems_8_2_b.js

@@ -0,0 +1,23 @@
+const utils = require('../../Utils')
+
+// 0(n)
+const sort = (A) => {
+    let i = -1
+    let j = A.length
+    while (i < j) {
+        while (A[i] != 1 && i < j) {
+            i++
+        }
+        while (A[j] != 0 && j > i) {
+            j--
+        }
+        utils.exchange(A, i, j)
+        i++
+        j--
+    }
+}
+
+
+let A = [0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1]
+sort(A)
+console.log(A)

ch_8/bucket_sort.js

@@ -0,0 +1,36 @@
+/**
+ * This is the non-linked-list version
+ * I'm just using arrays as buckets,
+ * Actually this is very slow now, because of the 
+ * Array.prototype.concat function, 
+ * I'll be implementing the linked-list version
+ * in future chapters
+ */
+const Utils = require('../Utils')
+const insertion_sort = require('../ch_2/insertion_sort')
+
+bucket_sort = (A) => {
+    let B = []
+    let C = []
+    let n = A.length
+    for (i in A) {
+        B.push(new Array())
+    }
+
+    for (let i = 0; i < n; i++) {
+        B[Math.floor(n * A[i])].push(A[i])
+    }
+
+    for (let i = 0; i < n; i++) {
+        insertion_sort(B[i])
+    }
+    
+    for (let i = 0; i < n; i++) {
+        C = C.concat(B[i])
+    }
+
+    return C
+}
+
+let A = Utils.randomArrayBetween0And1(10000)
+Utils.AlgorithmInfoLog(bucket_sort, [A], false)