Problem
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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 + 42 + 63 = 27)
Solution
用DFS搜索，dep表示深度。
/**
* // 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 {
public:
int getSum(int dep, vector<NestedInteger> &nestedList) {
int total = 0;
for(int i = 0; i < nestedList.size(); i++) {
if (nestedList[i].isInteger()) {
total += nestedList[i].getInteger() * dep;
} else {
total += getSum(dep + 1, nestedList[i].getList());
}
}
return total;
}
int depthSum(vector<NestedInteger>& nestedList) {
return getSum(1, nestedList);
}
};
