Euler

A list of the Project Euler problems I’ve solved with best solution times on a 2013 MacBook Pro.

The GitHub repo is private as Project Euler request solutions aren’t shared. But I enjoy thinking about these problems so if you want to tell me there’s a way faster solution I’ve missed or to ask about a problem, my contact details are on this page.

Timings

	Problem	Python
001	Multiples of 3 and 5	1.74 µs
002	Even Fibonacci Numbers	14.8 µs
003	Largest prime factor	134 ms
004	Largest palindrome product	951 ms
005	Smallest multiple	37.5 µs
006	Sum Square Difference	1.11 µs
007	10001st prime	5.99 s
008	Largest product in a series	4.12 ms
009	Special Pythagorean Triplet	22.1 s
010	Summation of primes	3.18 s
011	Largest product in a grid	832 µs
012	Highly Divisible Triangular Number	5.48 s
013	Large Sum	5.61 µs
014	Longest Collatz sequence	54.1 s
015	Lattice paths	16.3 µs
016	Power Digit Sum	37.1 ms
017	Number letter counts	1.01 ms
018	Maximum path sum I	34 ms
019	Counting Sundays	930 µs
020	Factorial digit sums	172 ms
021	Amicable Numbers	4.95 s
022	Names scores	24 ms
023
024	Lexicographic permutations	29.3 µs
025	1000-digit Fibonacci number	1.99 s
026
027
028
029
030
031	Coin Sums	2.9 s
032
033
034	Digit factorials	13 s
035	Circular Primes	13.3 s
036	Double-base palindrome	1.01 s
037
038
039	Integer right triangles	828 ms
040	Champernowne’s constant	854 ms
041
042	Coded Triangle Numbers	4.86 ms
043
044	Pentagonal numbers	17 s
045	Triangular, pentagonal, and hexagonal	55.9 ms
046	Goldbach’s other conjecture	411 ms
047	Distinct Prime Factors	60 s
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067	Maximum path sum II	9.23ms