继续预告大项目，鸽这么久也不是本意。主要是项目越写越大，功能越来越多有点停不下来。。。
希望能做出10h以上的视频。
今天讲一道 codewars 5级题。
腾讯讲解视频链接
https://v.qq.com/x/page/w0724xdcnih.html
b站讲解视频链接
https://www.bilibili.com/video/av26980703
题目
Inspired from real-world Brainf**k, we want to create an interpreter of that language which will support the following instructions ( the machine memory or 'data' should behave like a potentially infinite array of bytes, initialized to 0 ):
-
> increment the data pointer (to point to the next cell to the right).
-
< decrement the data pointer (to point to the next cell to the left).
-
+ increment (increase by one, truncate overflow: 255 + 1 = 0) the byte at the data pointer.
-
- decrement (decrease by one, treat as unsigned byte: 0 - 1 = 255 ) the byte at the data pointer.
-
. output the byte at the data pointer.
-
, accept one byte of input, storing its value in the byte at the data pointer.
-
[ if the byte at the data pointer is zero, then instead of moving the instruction pointer forward to the next command, jump it forward to the command after the matching ] command.
-
] if the byte at the data pointer is nonzero, then instead of moving the instruction pointer forward to the next command, jump it back to the command after the matching [ command.
The function will take in input...
-
the program code, a string with the sequence of machine instructions, the program input, a string, eventually empty, that will be interpreted as an array of bytes using each character's ASCII code and will be consumed by the , instruction
... and will return ...
-
the output of the interpreted code (always as a string), produced by the .
instruction.
SOLUTION
#include <string>
#include <vector>
#include <deque>
std::string brainLuck(std::string code, std::string input)
{
std::deque<unsigned char> memory;
memory.push_back(0);
int DataPointer = 0;
int inputpointer = 0;
std::string out = "";
for (int CodePointer = 0; CodePointer < code.size(); CodePointer++) {
switch (code[CodePointer])
{
case '>':
DataPointer++;
if (DataPointer == memory.size())memory.push_back(0);
break;
case '<':
DataPointer--;
if (DataPointer == -1) {
memory.push_front(0);
DataPointer = 0;
}
break;
case '+':
memory[DataPointer]++;
break;
case '-':
memory[DataPointer]--;
break;
case '.':
out.push_back(memory[DataPointer]);
break;
case ',':
memory[DataPointer] = input[inputpointer++];
break;
case '[': {
if (!memory[DataPointer]) {
int leftStack = 0;
CodePointer++;
for (; CodePointer < code.size(); CodePointer++) {
if (code[CodePointer] == '[')leftStack++;
else if (code[CodePointer] == ']')leftStack--;
if (leftStack == -1)break;
}
}
}break;
case ']': {
if (memory[DataPointer]) {
int RightStack = 0;
CodePointer--;
for (; CodePointer > -1; CodePointer--) {
if (code[CodePointer] == ']')RightStack++;
else if (code[CodePointer] == '[')RightStack--;
if (RightStack == -1)break;
}
}
}break;
default:
break;
}
}
return out;
}
交流qq：1980185974
微信：Huo-coding