class Solution {
    public boolean canReach(int[] arr, int start) {
        boolean[] visited = new boolean[arr.length];
        return dfs(arr, start, visited);
    }

    private boolean dfs(int[] arr, int current, boolean[] visited) {
        if (arr[current] == 0) {
            return true;
        }
        visited[current] = true;
        int left = current - arr[current];
        int right = current + arr[current];
        if (left >= 0 && !visited[left]) {
            if (dfs(arr, left, visited)) {
                return true;
            }
        }
        if (right < arr.length && !visited[right]) {
            if (dfs(arr, right, visited)) {
                return true;
            }
        }
        return false;
    }
}

/*
    arr = [4, 2, 3, 0, 3, 1, 2], start = 5

    dfs(..., 5, [0, 0, 0, 0, 0, 0, 0])
      arr[5] -> 1
      visited[5] = true
      left = 4
      right = 6

      dfs(..., left = 4, [0, 0, 0, 0, 0, 1, 0])
        arr[4] -> 3
        visited[4] = true
        left = 1
        right = 7

        dfs(..., left = 1, [0, 0, 0, 0, 1, 1, 0])
          arr[1] -> 2
          visited[1] = true
          left = -1
          right = 3

          dfs(..., right = 3, [0, 1, 0, 0, 1, 1, 0])
            arr[3] -> 0
            return true
          return true
        return true
    return true
*/