Alena And The Heater
题意翻译
给出两个长度为N的数组A,B,以及一种计算规律:
若t[i]=1,需满足t[i-1]=t[i-2]=t[i-3]=t[i-4]=0,以及max{A[i],A[i-1],A[i-2],A[i-3],A[i-4]} < l
若t[i]=0,需满足t[i-1]=t[i-2]=t[i-3]=t[i-4]=1,以及min{A[i],A[i-1],A[i-2],A[i-3],A[i-4]} > r
其他情况:t[i]=t[i-1](|l|,|r|≤10^9)
现在要使得运算一次的结果t=B,求满足条件的l,r(保证有解)
N≤100000
题目描述
"We've tried solitary confinement, waterboarding and listening to Just In Beaver, to no avail. We need something extreme."
"Little Alena got an array as a birthday present $ ... $ "
The array $ b $ of length $ n $ is obtained from the array $ a $ of length $ n $ and two integers $ l $ and $ r $ ( $ l<=r $ ) using the following procedure:
$ b_{1}=b_{2}=b_{3}=b_{4}=0 $ .
For all $ 5<=i<=n $ :
- $ b_{i}=0 $ if $ a_{i},a_{i-1},a_{i-2},a_{i-3},a_{i-4}>r $ and $ b_{i-1}=b_{i-2}=b_{i-3}=b_{i-4}=1 $
- $ b_{i}=1 $ if $ a_{i},a_{i-1},a_{i-2},a_{i-3},a_{i-4}<l $ and $ b_{i-1}=b_{i-2}=b_{i-3}=b_{i-4}=0 $
- $ b_{i}=b_{i-1} $ otherwise
You are given arrays $ a $ and $ b' $ of the same length. Find two integers $ l $ and $ r $ ( $ l<=r $ ), such that applying the algorithm described above will yield an array $ b $ equal to $ b' $ .
It's guaranteed that the answer exists.
输入输出格式
输入格式
The first line of input contains a single integer $ n $ ( $ 5<=n<=10^{5} $ ) — the length of $ a $ and $ b' $ .
The second line of input contains $ n $ space separated integers $ a_{1},...,a_{n} $ ( $ -10^{9}<=a_{i}<=10^{9} $ ) — the elements of $ a $ .
The third line of input contains a string of $ n $ characters, consisting of 0 and 1 — the elements of $ b' $ . Note that they are not separated by spaces.
输出格式
Output two integers $ l $ and $ r $ ( $ -10^{9}<=l<=r<=10^{9} $ ), conforming to the requirements described above.
If there are multiple solutions, output any of them.
It's guaranteed that the answer exists.
输入输出样例
输入样例 #1
5
1 2 3 4 5
00001
输出样例 #1
6 15
输入样例 #2
10
-10 -9 -8 -7 -6 6 7 8 9 10
0000111110
输出样例 #2
-5 5
说明
In the first test case any pair of $ l $ and $ r $ pair is valid, if $ 6<=l<=r<=10^{9} $ , in that case $ b_{5}=1 $ , because $ a_{1},...,a_{5}<l $ .