# LeetCode 354 Russian Doll Envelopes

## 题目描述

You have a number of envelopes with widths and heights given as a pair of integers (w, h). One envelope can fit into another if and only if both the width and height of one envelope is greater than the width and height of the other envelope.

What is the maximum number of envelopes can you Russian doll? (put one inside other)

Example:
Given envelopes = [[5,4],[6,4],[6,7],[2,3]], the maximum number of envelopes you can Russian doll is 3 ([2,3] => [5,4] => [6,7]).

## 一句话题意

n个信封，每个信封都有自己的宽高，并且当一个信封的宽高均严格大于另一个信封的宽高时，可以将后者套入前者中。