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:
| use vstd::prelude::*; | |
| fn main() {} | |
| verus! { | |
| pub struct Solution; | |
| impl Solution { | |
| pub open spec fn prefix_sum(cards: Seq<i32>, n: int) -> int | |
| decreases n | |
| { | |
| if n <= 0 { 0 } | |
| else { Self::prefix_sum(cards, n - 1) + cards[n - 1] as int } | |
| } | |
| pub open spec fn suffix_sum(cards: Seq<i32>, n: int) -> int | |
| decreases n | |
| { | |
| if n <= 0 { 0 } | |
| else { Self::suffix_sum(cards, n - 1) + cards[cards.len() - n] as int } | |
| } | |
| pub open spec fn max_score_spec(cards: Seq<i32>, k: int, i: int) -> int | |
| decreases k - i + 1 | |
| { | |
| if i > k { 0 } | |
| else { | |
| let score = Self::prefix_sum(cards, i) + Self::suffix_sum(cards, k - i); | |
| let rest = Self::max_score_spec(cards, k, i + 1); | |
| if score >= rest { score } else { rest } | |
| } | |
| } | |
| pub fn max_score(card_points: Vec<i32>, k: i32) -> (res: i32) | |
| requires | |
| 1 <= card_points.len(), | |
| card_points.len() <= 100_000, | |
| forall |i: int| 0 <= i < card_points.len() ==> 1 <= card_points[i] <= 10_000, | |
| 1 <= k, | |
| k <= card_points.len(), | |
| ensures | |
| res as int == Self::max_score_spec(card_points@, k as int, 0), | |
| { | |
| let n = card_points.len(); | |
| let k = k as usize; | |
| let mut left_sum = 0i32; | |
| let mut right_sum = 0i32; | |
| let mut i = 0usize; | |
| while i < k | |
| { | |
| left_sum = left_sum + card_points[i]; | |
| i = i + 1; | |
| } | |
| let mut best = left_sum; | |
| let mut i = 0usize; | |
| while i < k | |
| { | |
| let left_card_idx = k - 1 - i; | |
| let right_card_idx = n - 1 - i; | |
| left_sum = left_sum - card_points[left_card_idx]; | |
| right_sum = right_sum + card_points[right_card_idx]; | |
| let score = left_sum + right_sum; | |
| if left_sum + right_sum > best { | |
| best = left_sum + right_sum; | |
| } | |
| i = i + 1; | |
| } | |
| best | |
| } | |
| } | |
| } | |