// gamemap 由 info矩阵 构成， 每个info 包括一个坐标pos 和一个data。data 是str ，代表宝物的种类


    // from info pos , get the  longest way with same color
    private List<Pos> getLongest(MapInfo info, GameMap map, List<Pos> oldList)
    {
        List<List<Pos>> lists = new LinkedList<>();
        boolean found = false;

        // 遍历相邻节点，递归调用
        for (MapInfo nearInfo : GameUtil.getNearInfos(info.getPos(), map))
        {
            if (info.getData().equals(nearInfo.getData()) && !oldList.contains(nearInfo.getPos()))
            {
                found = true;
                List<Pos> tmpList = new LinkedList<>(oldList);
                tmpList.add(nearInfo.getPos());
                tmpList = getLongest(nearInfo, map, tmpList);
                lists.add(tmpList);
            }
        }
        if (!found)
        {
            return oldList;
        }
        // 返回最长的那个
        return lists.stream().max(Comparator.comparingInt(List::size)).orElse(null);
    }

input 示例

[input]( http://www.jianshu.com/p/4a4e74755feb )

output

{"moves":[{"x":1,"y":1},{"x":0,"y":1},{"x":0,"y":2},{"x":0,"y":3},{"x":1,"y":3},{"x":1,"y":2},{"x":2,"y":1},{"x":3,"y":0},{"x":3,"y":1},{"x":4,"y":0},{"x":5,"y":0},{"x":6,"y":0}]}