Grokking Algorithms

O
OCR (optical character
recognition) 199–201
P
parallel algorithms 208
partitioning 61
person_is_seller function 108, 111
pivot element 60
pop (remove and read) action 42
Print function 43
print_items function 67
private key, Diie-Hellman 218
probabilistic data structure 212
pseudocode 38, 40, 182
public key, Diie-Hellman 218
push (insert) action 42
Pythagorean formula 191
Q
queues 30–31
quicksort, Big O notation and
66–71

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238
average case vs. worst case
68–71
exercises 72
merge sort vs. quicksort 67–68
R
random access 30
recommendations system, building
189–194
recursion 37–49
base case and recursive case
40–41
call stack with 45–50
overview 37–39
regression 196
resizing 91
run time 
common run times 15–16
growth of at diferent rates
11–13
overview 10
S
searches
binary search 3–10
as better way to search 5–7
exercises 6–9
overview 3–4
running time 10
breadt
h-irst search
graphs and 99–104
implementing 105–106
implementing algorithm
107–113
selection sort 32–33
sequential access 30
set-covering problem 146–151
approximation algorithms
calculating answer 149
code for setup 147–148
sets 149–150
exercise 152
overview 146
s
et diference 150
set intersection 150
sets 148
set union 150
SHA algorithms 213–216
checking passwords 215–216
comparin
g iles 214
overview 213
SHA (Secure Hash Algorithm) 
function 92, 214
shortest path 98, 128
signals, processing 207
Simhash 216, 217
simple search 5, 11, 200
SQL query 209
stacks 42–49
call stack 43–45
call stack with recursion 45–50
exercise 45, 49–50
overview 42
states_covered set 149
states_for_station 151
states_needed 151
stock market, predicting 201
strings, mapping to numbers 76
sum function 57, 59