[Leetcode] 339. Nested List Weight Sum 解题报告_339 nested-list-weight-sum-优快云博客

本文链接：https://blog.youkuaiyun.com/magicbean2/article/details/76886997

本文介绍了一种针对嵌套整数列表的加权深度求和算法。该算法通过递归方式遍历列表中所有元素，并根据其深度计算加权总和。例如，对于列表 [[1,1],2,[1,1]]，算法返回10；对于 [1,[4,[6]]]，返回27。代码实现使用C++完成。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

题目：

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)

思路：

很简单的一道递归题目，没什么可说的。

代码：

/**
 * // 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 depthSum(vector<NestedInteger>& nestedList) {
        return depthSum(nestedList, 1);
    }
private:
    int depthSum(vector<NestedInteger>& nestedList, int level) {
        int ret = 0;
        for (int i = 0; i < nestedList.size(); ++i) {
            if (nestedList[i].isInteger()) {
                ret += nestedList[i].getInteger() * level;
            }
            else {
                ret += depthSum(nestedList[i].getList(), level + 1);
            }
        }
        return ret;
    }
};