Technology Quote by Robert Sedgewick
![““public class Merge { private static Comparable[] aux; // auxiliary array for merges public static void sort(Comparable[] a) { aux = new Comparable[a.length]; // Allocate space just once. sort(a, 0, a.length - 1); } private static void sort(Comparable[] a, int lo, int hi) { // Sort a[lo..hi]. if (hi” quote by Robert Sedgewick](https://sms4smile.com/quotes/img-quotes/fa3/robert-sedgewick-81232_quote_public-class-merge-private-static-compar_1184442.jpg)
““public class Merge { private static Comparable[] aux; // auxiliary array for merges public static void sort(Comparable[] a) { aux = new Comparable[a.length]; // Allocate space just once. sort(a, 0, a.length - 1); } private static void sort(Comparable[] a, int lo, int hi) { // Sort a[lo..hi]. if (hi <= lo) return; int mid = lo + (hi - lo)/2; sort(a, lo, mid); // Sort left half. sort(a, mid+1, hi); // Sort right half. merge(a, lo, mid, hi); // Merge results (code on page 271). } }””
About This Quote
Source Book: Algorithms, 4th Edition, Robert Sedgewick & Kevin Wayne, 2011
The code shows a classic top‑down merge sort that allocates an auxiliary array once and recursively sorts subarrays before merging them.
In simple terms: Merge sort uses divide and conquer with a reusable buffer.
Key Takeaway
Allocate buffer once, then sort recursively.
Themes
algorithms
sorting
efficiency
Mood
analytical
instructional
Type
technical
educational
When to use this quote
- sorting large datasets
- educational demos
- performance tuning
Key Concepts
divide and conquer
recursion
auxiliary storage
Questions to Reflect On
- How does allocating the buffer once improve performance?
- When is recursion preferable to iteration?
A Different Perspective
Requires extra memory proportional to input size.
![“public class MergeBU { private static Comparable[] aux; // auxiliary array for merges // See page 271 for merge() code. public static void sort(Comparable[] a) { // Do lg N passes of pairwise merges. int N = a.length; aux = new Comparable[N]; for (int sz = 1; sz < N; sz = sz+sz) // sz: subarray…” quote by Robert Sedgewick](https://sms4smile.com/quotes/img-quotes/ab9/robert-sedgewick-81232_quote_public-class-mergebu-private-static-comp_3206463.jpg)
![“Sorting gets harder as time goes on--it requires a sort of ruthless decisiveness, while indecision results in endless dithering. Five moves, they say, equal a fire. But those who haven't moved may begin to need a fire. [p. 38]” quote by Mary Catherine Bateson](https://sms4smile.com/quotes/img-quotes/1df/mary-catherine-bateson-11582_age_sorting-gets-harder-as-time-goes-on-it-r_2636387.jpg)
![“The middle ages did not care much for alphabetical order, because they were committed to rational order. To the medieval mind, the universe [is] a harmonious whole whose parts are related to one another. It was the responsibility of the author or scholar to discern these rational relationships…” quote by Matthew Battles](https://sms4smile.com/quotes/img-quotes/da2/matthew-battles-50730_middle-ages_the-middle-ages-did-not-care-much-for-al_2819215.jpg)
