# 归档 2016年9月25日

## LeetCode Weekly Contest 6解题报告 作者是 在线疯狂 发布于 2016年9月25日 在 LeetCode.

LeetCode Weekly Contest 6是LeetCode举办的第五场正式周赛，共4道题目，比赛时长2.5小时。

LeetCode 404. Sum of Left Leaves

LeetCode 405. Convert a Number to Hexadecimal

LeetCode 406. Queue Reconstruction by Height

LeetCode 407. Trapping Rain Water II

## 题目描述：

LeetCode 407. Trapping Rain Water II

Given an `m x n` matrix of positive integers representing the height of each unit cell in a 2D elevation map, compute the volume of water it is able to trap after raining ...

## 题目描述：

LeetCode 406. Queue Reconstruction by Height

Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers `(h, k)`, where `h` is the height of the person and `k ...`

## 题目描述：

LeetCode 405. Convert a Number to Hexadecimal

Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used.

IMPORTANT:
You must not use any method provided by the library which converts ...

## 题目描述：

LeetCode 404. Sum of Left Leaves

Find the sum of all left leaves in a given binary tree.

Example:

```    3
/ \
9  20
/  \
15   7

There are two left leaves in the binary tree, with values 9 and 15 respectively ...```