fn put_string(array: &mut Vec<String>, input: String) { array.push(input) } fn find_string(array: &[String], input: &str) -> Option<usize>

fn put_string(array: &mut Vec<String>, input: String) { array.push(input) } fn find_string(array: &[String], input: &str) -> Option<usize> { for i in 0..array.len() { if &array[i] == input { return Some(i); } } None // or perhaps more idiomatically: // array.iter().position(|s| s.as_str() == input) } #[test] fn test_find_string() { let mut array = vec![]; put_string(&mut array, “foo”.to_string()); put_string(&mut array, “bar”.to_string()); assert_eq!(find_string(&array, “foo”), Some(0)); assert_eq!(find_string(&array, “bar”), Some(1)); assert_eq!(find_string(&array, “quux”), None); } If our array is sorted, the performance of the function should improve due to better branch prediction. But we’d be better of rewriting it as binary search in that case. What kind of salary are you offering?