Buy two chocolates

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![1, 2, 2], 3);
    let expected = 0;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![3, 2, 3], 3);
    let expected = 3;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![1, 1], 2);
    let expected = 0;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![5, 5, 5], 9);
    let expected = 9;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![1, 100], 100);
    let expected = 100;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t6() {
    let start = std::time::Instant::now();
    let val = Solution::buy_choco(vec![10, 20, 30, 40], 50);
    let expected = 20;
    log_result!(val == expected, "t6", start, &expected, &val);
    assert_eq!(val, expected);
}