Function librualg::string::kmp_first

pub fn kmp_first(t: &str, p: &str) -> Option<usize>

Knuth–Morris–Pratt string-searching algorithm (or KMP algorithm). Return first occurrence of a substring.

 use librualg::string::kmp_first;

 assert_eq!(kmp_first("cbcdabcd", "abc"), Some(4));
 assert_eq!(kmp_first("cbcdabcd", "ebc"), None);