Rust Implementation of Problem 18
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Includes
Problem Solution
- pub fn problems::p0018::p0018() -> utils::Answer
1/*
2Project Euler Problem 18
3
4Thinking from the bottom up got the answer
5
6Problem:
7
8By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top
9to bottom is 23.
10
11.. code-block::
12
13 3
14 7 4
15 2 4 6
16 8 5 9 3
17
18That is, 3 + 7 + 4 + 9 = 23.
19
20Find the maximum total from top to bottom of the triangle below:
21
22.. code-block::
23
24 75
25 95 64
26 17 47 82
27 18 35 87 10
28 20 04 82 47 65
29 19 01 23 75 03 34
30 88 02 77 73 07 63 67
31 99 65 04 28 06 16 70 92
32 41 41 26 56 83 40 80 70 33
33 41 48 72 33 47 32 37 16 94 29
34 53 71 44 65 25 43 91 52 97 51 14
35 70 11 33 28 77 73 17 78 39 68 17 57
36 91 71 52 38 17 14 91 43 58 50 27 29 48
37 63 66 04 68 89 53 67 30 73 16 69 87 40 31
38 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
39
40NOTE: As there are only 16384 routes, it is possible to solve this problem by trying every route. However, Problem 67,
41is the same challenge with a triangle containing one-hundred rows; it cannot be solved by brute force, and requires a
42clever method! ;o)
43*/
44use crate::include::triangles::reduce_triangle;
45use crate::include::utils::Answer;
46
47
48pub fn p0018() -> Answer {
49 let rows = vec![
50 vec![75, ],
51 vec![95, 64],
52 vec![17, 47, 82],
53 vec![18, 35, 87, 10],
54 vec![20, 4, 82, 47, 65],
55 vec![19, 1, 23, 75, 3, 34],
56 vec![88, 2, 77, 73, 7, 63, 67],
57 vec![99, 65, 4, 28, 6, 16, 70, 92],
58 vec![41, 41, 26, 56, 83, 40, 80, 70, 33],
59 vec![41, 48, 72, 33, 47, 32, 37, 16, 94, 29],
60 vec![53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14],
61 vec![70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57],
62 vec![91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48],
63 vec![63, 66, 4, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31],
64 vec![ 4, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 4, 23]
65 ];
66 return Answer::Int(reduce_triangle(rows).into());
67}