Given a nested list of integers, return the sum of all integers in the list weighted by their depth.
Each element is either an integer, or a list -- whose elements may also be integers or other lists.
Example 1:Given the list [[1,1],2,[1,1]], return 10. (four 1's at depth 2, one 2 at depth 1)
Example 2:Given the list [1,[4,[6]]], return 27. (one 1 at depth 1, one 4 at depth 2, and one 6 at depth 3; 1 + 4*2 + 6*3 = 27)
/** * // 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 { public int depthSum(List<NestedInteger> nestedList) { int sum = 0; int level = 1; while(nestedList.size()!=0) { List<NestedInteger> list = new LinkedList<NestedInteger>(); for(int i=0;i<nestedList.size();i++) { if(nestedList.get(i).isInteger()) { sum = sum + nestedList.get(i).getInteger()*level; } else { list.addAll(nestedList.get(i).getList()); } } level++; nestedList = list; } return sum; } }
addAll() method:
http://beginnersbook.com/2013/12/java-arraylist-addall-int-index-collection-c-method-example/
转载于:https://www.cnblogs.com/hygeia/p/5684449.html
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