Function unique_paths 

pub fn unique_paths(rows: usize, cols: usize) -> u64

Panjarada yo’llar soni: rows × cols to’rning chap-yuqori burchagidan o’ng-pastki burchagiga faqat o’ngga va pastga yurib nechta yo’l bor?

Holat: dp[j] = joriy qatordagi j -katakka nechta yo’l bor. O’tish: dp[j] += dp[j-1] (yuqoridan + chapdan).

• Time: O(rows·cols), Space: O(cols).

Misol

use rust_algorithms::dp::unique_paths;

assert_eq!(unique_paths(3, 3), 6);
assert_eq!(unique_paths(1, 10), 1);
assert_eq!(unique_paths(0, 5), 0);