平面列表
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。
您在真实的面试中是否遇到过这个题？
Yes
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
* class NestedInteger {
* public:
* // Return true if this NestedInteger holds a single integer,
* // rather than a nested list.
* bool isInteger() const;
*
* // Return the single integer that this NestedInteger holds,
* // if it holds a single integer
* // The result is undefined if this NestedInteger holds a nested list
* int getInteger() const;
*
* // Return the nested list that this NestedInteger holds,
* // if it holds a nested list
* // The result is undefined if this NestedInteger holds a single integer
* const vector<NestedInteger> &getList() const;
* };
*/
class Solution {
vector<int> res;
public:
// @param nestedList a list of NestedInteger
// @return a list of integer
vector<int> flatten(const vector<NestedInteger> &nestedList) {
// Write your code here
int size = nestedList.size();
for( int i = 0 ; i < size ; i++ ){
if(nestedList[i].isInteger() ){
res.push_back(nestedList[i].getInteger() );
}
else{
flatten(nestedList[i].getList());
}
}
return res;
}
};