Rust Implementation of Problem 8

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Problem Solution

pub fn problems::p0008::p0008() -> utils::Answer
 1/*
 2Project Euler Problem 8
 3
 4In Python I did this with an iterator, but that is more cumbersome here,
 5so I just did it with a loop that slices.
 6
 7Problem:
 8
 9The four adjacent digits in the 1000-digit number that have the greatest
10product are 9 × 9 × 8 × 9 = 5832.
11
1273167176531330624919225119674426574742355349194934
1396983520312774506326239578318016984801869478851843
1485861560789112949495459501737958331952853208805511
1512540698747158523863050715693290963295227443043557
1666896648950445244523161731856403098711121722383113
1762229893423380308135336276614282806444486645238749
1830358907296290491560440772390713810515859307960866
1970172427121883998797908792274921901699720888093776
2065727333001053367881220235421809751254540594752243
2152584907711670556013604839586446706324415722155397
2253697817977846174064955149290862569321978468622482
2383972241375657056057490261407972968652414535100474
2482166370484403199890008895243450658541227588666881
2516427171479924442928230863465674813919123162824586
2617866458359124566529476545682848912883142607690042
2724219022671055626321111109370544217506941658960408
2807198403850962455444362981230987879927244284909188
2984580156166097919133875499200524063689912560717606
3005886116467109405077541002256983155200055935729725
3171636269561882670428252483600823257530420752963450
32
33Find the thirteen adjacent digits in the 1000-digit number that have the
34greatest product. What is the value of this product?
35*/
36use crate::include::utils::Answer;
37
38pub fn p0008() -> Answer {
39    let string = concat!(
40        "73167176531330624919225119674426574742355349194934",
41        "96983520312774506326239578318016984801869478851843",
42        "85861560789112949495459501737958331952853208805511",
43        "12540698747158523863050715693290963295227443043557",
44        "66896648950445244523161731856403098711121722383113",
45        "62229893423380308135336276614282806444486645238749",
46        "30358907296290491560440772390713810515859307960866",
47        "70172427121883998797908792274921901699720888093776",
48        "65727333001053367881220235421809751254540594752243",
49        "52584907711670556013604839586446706324415722155397",
50        "53697817977846174064955149290862569321978468622482",
51        "83972241375657056057490261407972968652414535100474",
52        "82166370484403199890008895243450658541227588666881",
53        "16427171479924442928230863465674813919123162824586",
54        "17866458359124566529476545682848912883142607690042",
55        "24219022671055626321111109370544217506941658960408",
56        "07198403850962455444362981230987879927244284909188",
57        "84580156166097919133875499200524063689912560717606",
58        "05886116467109405077541002256983155200055935729725",
59        "71636269561882670428252483600823257530420752963450"
60    );
61    let mut answer: u64 = 0;
62    for i in 0..(string.len() - 13) {
63        let slice = &string[i..(i + 13)];
64        let mut prod: u64 = 1;
65        for c in slice.bytes() {
66            prod *= (c - b'0') as u64;
67        }
68        if prod > answer {
69            answer = prod;
70        }
71    }
72    return Answer::Int(answer.into());
73}