0797 All Paths From Source to Target

0797 All Paths From Source to Target.java

class Solution {
    public List<List<Integer>> allPathsSourceTarget(int[][] graph) {
        List<List<Integer>> res = new ArrayList<>();
        helper(graph, 0, new ArrayList<>(), res);
        return res;
    }
    private void helper(int[][] graph, int i, List<Integer> path, List<List<Integer>> res) {
        path.add(i);
        if (i == graph.length - 1) {
            res.add(new ArrayList<Integer>(path));
        } else {
            for (int nxt: graph[i])
                helper(graph, nxt, path, res);
        }
        path.remove(path.size() - 1);
    }
}