Method next_permutation

47. Permutations II/src/main.rs:21–38

(nums: &mut Vec<i32>)

    }

    pub fn next_permutation(nums: &mut Vec<i32>) {
        if nums.len() <= 1 { return }
        let mut i = nums.len() - 2;
        while let false = nums[i] < nums[i + 1] {
            if i != 0 {
                i -= 1
            } else {
                nums.reverse();
                return
            }
        }
        let mut j = nums.len() - 1;
        while let false = nums[i] < nums[j] {
            j -= 1;
        }
        nums.swap(i, j);
        nums[i+1..].reverse()
    }
}

#[cfg(test)]