Easy
是L家tag题，又是DFS就比较想刷，然后算是bug free吧
/**
* // 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<NestedInteger> getList();
* }
*/
public class Solution {
int sum = 0;
public int depthSum(List<NestedInteger> nestedList) {
if (nestedList == null || nestedList.size() == 0){
return 0;
}
dfsHelper(nestedList, 1);
return sum;
}
private void dfsHelper(List<NestedInteger> niList, int level){
for (NestedInteger ni : niList){
if (ni.isInteger()){
sum += ni.getInteger() * level;
} else {
dfsHelper(ni.getList(), level + 1);
}
}
}
}
看看提交记录，最近状态是比较好，进步也是实实在在的.
image.png
