Codeforces Beta Round #96 (Div. 2) （二进制数取模）

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本文详细解析了将Brainfuck指令集转换为Unary数制的算法过程，并提供了实例演示，帮助理解转换逻辑及计算结果。

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Unary is a minimalistic Brainfuck dialect in which programs are written using only one token.

Brainfuck programs use 8 commands: "+", "-", "[", "]", "<", ">", "." and "," (their meaning is not important for the purposes of this problem). Unary programs are created from Brainfuck programs using the following algorithm. First, replace each command with a corresponding binary code, using the following conversion table:

">" → 1000,
"<" → 1001,
"+" → 1010,
"-" → 1011,
"." → 1100,
"," → 1101,
"[" → 1110,
"]" → 1111.

Next, concatenate the resulting binary codes into one binary number in the same order as in the program. Finally, write this number using unary numeral system — this is the Unary program equivalent to the original Brainfuck one.

You are given a Brainfuck program. Your task is to calculate the size of the equivalent Unary program, and print it modulo1000003 (10⁶ + 3).

<p< p="" style="font-family: verdana, arial, sans-serif; font-size: 14px; line-height: 21px; "><p< p="">

Input

<p< p="">

The input will consist of a single line p which gives a Brainfuck program. String p will contain between 1 and 100 characters, inclusive. Each character of p will be "+", "-", "[", "]", "<", ">", "." or ",".

<p< p=""><p< p="">

Output

<p< p="">

Output the size of the equivalent Unary program modulo 1000003 (10⁶ + 3).

<p< p=""><p< p="">

Sample test(s)

<p< p=""><p< p="">

input

,.

output

input

++++[>,.<-]

output

<p< p=""><p< p="">

Note

<p< p="">

To write a number n in unary numeral system, one simply has to write 1 n times. For example, 5 written in unary system will be 11111.

In the first example replacing Brainfuck commands with binary code will give us 1101 1100. After we concatenate the codes, we'll get 11011100 in binary system, or 220 in decimal. That's exactly the number of tokens in the equivalent Unary program.

#include<cstring>
#include<iostream>
using namespace std;

char table[8][5] = {
    "1000",
    "1001",
    "1010",
    "1011",
    "1100",
    "1101",
    "1110",
    "1111"
};

char str[300];
int hash[300];
const int P = 1000003;

int main()
{
    hash['>'] = 0;
    hash['<'] = 1;
    hash['+'] = 2;
    hash['-'] = 3;
    hash['.'] = 4;
    hash[','] = 5;
    hash['['] = 6; 
    hash[']'] = 7;

    cin >> str;
    int len = strlen(str);
    int res = 0;
    for ( int i = 0; i < len; i++ )
        for ( int j = 0; j < 4; j++ )
            res = ( res * 2 + table[ hash[str[i]] ][j] - '0' ) % P;
    cout << res << endl;
    return 0;
}