平面列表
题目描述
给定一个列表，该列表中的每个要素要么是个列表，要么是整数。将其变成一个只包含整数的简单列表。
注意事项
如果给定的列表中的要素本身也是一个列表，那么它也可以包含列表。样例
给定 [1,2,[1,2]]，返回 [1,2,1,2]。
给定 [4,[3,[2,[1]]]]，返回 [4,3,2,1]。
/**
* // This is the interface that allows for creating nested lists.
* // You should not implement it, or speculate about its implementation
* public interface NestedInteger {
*
* // @return true if this NestedInteger holds a single integer,
* // rather than a nested list.
* public boolean isInteger();
*
* // @return the single integer that this NestedInteger holds,
* // if it holds a single integer
* // Return null if this NestedInteger holds a nested list
* public Integer getInteger();
*
* // @return the nested list that this NestedInteger holds,
* // if it holds a nested list
* // Return null if this NestedInteger holds a single integer
* public List getList();
* }
*/ 算法分析：
思路很简单，就是递归
public class Solution {
// @param nestedList a list of NestedInteger
// @return a list of integer
public List flatten(List nestedList) {
// Write your code here
Listlist=new ArrayList<>();
doFlatten(nestedList, list);
return list;
}
public static void doFlatten(List nestedList,Listlist){
if(nestedList!=null){
for(NestedInteger nList:nestedList){
if(nList.isInteger()){
list.add(nList.getInteger());
}
else{
doFlatten(nList.getList(), list);
}
}
}
}
}