Method combine

77-combinations.rs:17–22

(n: i32, k: i32)

    }

    pub fn combine(n: i32, k: i32) -> Vec<Vec<i32>> {
        let mut path = vec![];
        let mut ret = vec![];
        Self::backtrace(n, k as usize, 1, &mut path, &mut ret);
        ret
    }
}

fn main() {