实现类似寄存器_循环移位_的算法

    vector<vector<int>> direc {{0,1}, {1,0}, {0,-1}, {-1,0};
    int direcIndex = 0;
    
    if (instruction == 'L') {
        direcIndex += 3;
        direcIndex %= 4;
    } else if (instruction == 'R') {
        direcIndex++;
        direcIndex %= 4;
    }
    

先加，再取余