如果是1000个点，要求返回组大小为s的所有组合，并且把组合结果保存下来，该怎么做呢？这个时候感觉递归就不可以了，肯定会内存不够

Question

public static void bfs(int s, int start, ArrayList<GraphPoints<MultiDim>> list, ArrayList<GraphPoints<MultiDim>> now, ArrayList<ArrayList<GraphPoints<MultiDim>>> ans) {
        if(now.size() == s) {
            ans.add(now);
        }else {
            for(int i=start;i<list.size();i++) {
                ArrayList<GraphPoints<MultiDim>> temp = new ArrayList<>(now);
                temp.add(list.get(i));
                bfs(s,i+1,list,temp,ans);
            }
        }
    }

我自己是这么做的，然后就显示“java.lang.OutOfMemoryError: GC overhead limit exceeded”

Answer 1

temp导致的吧

public static void bfs(int targetSize, int start, List<GraphPoints<MultiDim>> pointsList, List<GraphPoints<MultiDim>> currentList, List<List<GraphPoints<MultiDim>>> resultList) {
    if (currentList.size() == targetSize) {
        resultList.add(new ArrayList<>(currentList));
    } else {
        for (int i = start; i < pointsList.size(); i++) {
            currentList.add(pointsList.get(i));
            bfs(targetSize, i + 1, pointsList, currentList, resultList);
            currentList.remove(currentList.size() - 1); // 回溯，移除最后一个元素
        }
    }
}
```java

```