Datasets:
Tasks:
Text Generation
Modalities:
Text
Formats:
json
Languages:
English
Size:
< 1K
ArXiv:
Tags:
competitive-programming
code-generation
specification-generation
proof-generation
verification
rust
License:
File size: 2,472 Bytes
b2a430f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | use vstd::prelude::*;
fn main() {}
verus! {
pub struct Solution;
impl Solution {
pub open spec fn circular_sum(code: Seq<i32>, n: int, start: int, count: int) -> int
decreases count,
{
if count <= 0 || n <= 0 {
0
} else {
code[start % n] as int + Self::circular_sum(code, n, start + 1, count - 1)
}
}
pub open spec fn decrypt_val(code: Seq<i32>, n: int, k: int, i: int) -> int {
if k > 0 {
Self::circular_sum(code, n, i + 1, k)
} else if k < 0 {
Self::circular_sum(code, n, i + n + k, -k)
} else {
0
}
}
pub fn decrypt(code: Vec<i32>, k: i32) -> (result: Vec<i32>)
requires
1 <= code@.len() <= 100,
forall|i: int| 0 <= i < code@.len() ==> 1 <= #[trigger] code@[i] <= 100,
-(code@.len() as int - 1) <= k as int <= code@.len() as int - 1,
ensures
result@.len() == code@.len(),
forall|i: int|
0 <= i < code@.len() ==> (#[trigger] result@[i]) as int == Self::decrypt_val(
code@,
code@.len() as int,
k as int,
i,
),
{
let n = code.len();
let mut result: Vec<i32> = Vec::new();
if k == 0 {
let mut i: usize = 0;
while i < n {
result.push(0);
i = i + 1;
}
return result;
}
let mut sum: i32 = 0;
if k > 0 {
let mut j: usize = 0;
while j < k as usize {
sum = sum + code[(1 + j) % n];
j = j + 1;
}
result.push(sum);
let mut i: usize = 1;
while i < n {
sum = sum - code[i % n] + code[(i + k as usize) % n];
result.push(sum);
i = i + 1;
}
} else {
let abs_k: usize = (-k) as usize;
let mut j: usize = 0;
while j < abs_k {
sum = sum + code[(n - abs_k + j) % n];
j = j + 1;
}
result.push(sum);
let mut i: usize = 1;
while i < n {
sum = sum - code[(i + n - abs_k - 1) % n] + code[(i + n - 1) % n];
result.push(sum);
i = i + 1;
}
}
result
}
}
}
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