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Codeforces Round #443 (Div. 2) C. Short Program
阅读量:6302 次
发布时间:2019-06-22

本文共 2026 字,大约阅读时间需要 6 分钟。

C. Short Program
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

Petya learned a new programming language CALPAS. A program in this language always takes one non-negative integer and returns one non-negative integer as well.

In the language, there are only three commands: apply a bitwise operation AND, OR or XOR with a given constant to the current integer. A program can contain an arbitrary sequence of these operations with arbitrary constants from 0 to 1023. When the program is run, all operations are applied (in the given order) to the argument and in the end the result integer is returned.

Petya wrote a program in this language, but it turned out to be too long. Write a program in CALPAS that does the same thing as the Petya's program, and consists of no more than 5 lines. Your program should return the same integer as Petya's program for all arguments from 0 to 1023.

Input

The first line contains an integer n (1 ≤ n ≤ 5·105) — the number of lines.

Next n lines contain commands. A command consists of a character that represents the operation ("&", "|" or "^" for AND, OR or XOR respectively), and the constant xi0 ≤ xi ≤ 1023.

Output

Output an integer k (0 ≤ k ≤ 5) — the length of your program.

Next k lines must contain commands in the same format as in the input.

Examples
Input
3 | 3 ^ 2 | 1
Output
2 | 3 ^ 2
Input
3 & 1 & 3 & 5
Output
1 & 1
Input
3 ^ 1 ^ 2 ^ 3
Output
0
Note

You can read about bitwise operations in .

Second sample:

Let x be an input of the Petya's program. It's output is ((x&1)&3)&5 = x&(1&3&5) = x&1. So these two programs always give the same outputs.

/* 题意:给出一段程序,只有三种操作,^ & |,然后让你输出一段不超过5行的程序使得运算结果和给出程序的运算结果相同 思路:经过如果操作之后,总共十位二进制数,有:确定为1的,确定为0的,不变的,是原来的相反的,然后分别讨论四种     情况 */#include 
#define MAXN 500005#define MAXK 2using namespace std;int n;char str[MAXN][MAXK];int a[MAXN];int ora,xora,anda;inline int cal(int x){ for(int i=0;i

 

转载于:https://www.cnblogs.com/wuwangchuxin0924/p/7744245.html

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