Summer Practice Report

题意翻译

给定 $n$ 个字符串，第 $i$ 个字符串由 $x_i$ 个 `T` 与 $y_i$ 个 `F` 构成。问是否有办法重排每个字符串，使得 $n$ 个字符串首尾相接成的长字符串中没有连续 $k +1$ 个相同字符

题目描述

Vova has taken his summer practice this year and now he should write a report on how it went. Vova has already drawn all the tables and wrote down all the formulas. Moreover, he has already decided that the report will consist of exactly $ n $ pages and the $ i $ -th page will include $ x_i $ tables and $ y_i $ formulas. The pages are numbered from $ 1 $ to $ n $ . Vova fills the pages one after another, he can't go filling page $ i + 1 $ before finishing page $ i $ and he can't skip pages. However, if he draws strictly more than $ k $ tables in a row or writes strictly more than $ k $ formulas in a row then he will get bored. Vova wants to rearrange tables and formulas in each page in such a way that he doesn't get bored in the process. Vova can't move some table or some formula to another page. Note that the count doesn't reset on the start of the new page. For example, if the page ends with $ 3 $ tables and the next page starts with $ 5 $ tables, then it's counted as $ 8 $ tables in a row. Help Vova to determine if he can rearrange tables and formulas on each page in such a way that there is no more than $ k $ tables in a row and no more than $ k $ formulas in a row.

输入输出格式

输入格式

The first line contains two integers $ n $ and $ k $ ( $ 1 \le n \le 3 \cdot 10^5 $ , $ 1 \le k \le 10^6 $ ). The second line contains $ n $ integers $ x_1, x_2, \dots, x_n $ ( $ 1 \le x_i \le 10^6 $ ) — the number of tables on the $ i $ -th page. The third line contains $ n $ integers $ y_1, y_2, \dots, y_n $ ( $ 1 \le y_i \le 10^6 $ ) — the number of formulas on the $ i $ -th page.

输出格式

Print "YES" if Vova can rearrange tables and formulas on each page in such a way that there is no more than $ k $ tables in a row and no more than $ k $ formulas in a row. Otherwise print "NO".

输入输出样例

输入样例 #1

2 2
5 5
2 2

输出样例 #1

YES

输入样例 #2

2 2
5 6
2 2

输出样例 #2

NO

输入样例 #3

4 1
4 1 10 1
3 2 10 1

输出样例 #3

YES

说明

In the first example the only option to rearrange everything is the following (let table be 'T' and formula be 'F'): - page $ 1 $ : "TTFTTFT" - page $ 2 $ : "TFTTFTT" That way all blocks of tables have length $ 2 $ . In the second example there is no way to fit everything in such a way that there are no more than $ 2 $ tables in a row and $ 2 $ formulas in a row.