Maximum distance between unequal words in array i

#[test]
fn test_diff_at_ends() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["x".to_string(), "a".to_string(), "a".to_string(), "a".to_string(), "y".to_string()]);
    let expected = 5;
    log_result!(val == expected, "test_diff_at_ends", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example1() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["leetcode".to_string(), "leetcode".to_string(), "codeforces".to_string()]);
    let expected = 3;
    log_result!(val == expected, "test_example1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example2() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["a".to_string(), "b".to_string(), "c".to_string(), "a".to_string(), "a".to_string()]);
    let expected = 4;
    log_result!(val == expected, "test_example2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example3() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["z".to_string(), "z".to_string(), "z".to_string()]);
    let expected = 0;
    log_result!(val == expected, "test_example3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_two_different() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["a".to_string(), "b".to_string()]);
    let expected = 2;
    log_result!(val == expected, "test_two_different", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_two_same() {
    let start = std::time::Instant::now();
    let val = Solution::max_distance(vec!["a".to_string(), "a".to_string()]);
    let expected = 0;
    log_result!(val == expected, "test_two_same", start, &expected, &val);
    assert_eq!(val, expected);
}