dec1make0.cpp

#include <vector>
#include <iostream>
#include <cstdio>

static bool isall0(const std::vector<unsigned>& a)
{
    for(unsigned x : a)
        if(x)
            return false;

    return true;
}

static std::vector<unsigned> dec1(std::vector<unsigned> a)
{
    for(unsigned& x : a)
        if(x)
            --x;

    return a;
}

static std::vector<unsigned> mak0(std::vector<unsigned> a)
{
    for(unsigned& x : a)
    {
        if(x)
        {
            x = 0;
            break;
        }
    }
    return a;
}

static void pvec(const char * a, const std::vector<unsigned>& b)
{
    std::cout << a;
    for(unsigned x : b)
        std::printf("%3u, ", x);

    std::cout << std::endl;
}

enum action {action_d1, action_m0};

static unsigned steps(const std::vector<unsigned>& a, std::vector<action> * whatdo)
{
    if(isall0(a))
        return 0;

    const unsigned x = steps(dec1(a), 0x0);
    const unsigned y = steps(mak0(a), 0x0);
    const unsigned ret = 1 + std::min<unsigned>(x, y);

    if(!whatdo)
        return ret;

    if(x <= y)
    {
        whatdo->push_back(action_d1);
        steps(dec1(a), whatdo);
    }
    else
    {
        whatdo->push_back(action_m0);
        steps(mak0(a), whatdo);
    }

    return ret;
}

int main()
{
    std::vector<unsigned> a;
    std::vector<action> whatdo;
    unsigned in;
    while(std::cin >> in)
        a.push_back(in);

    const unsigned z = steps(a, &whatdo);
    pvec("For           : ", a);
    std::cout << "Answer is: " << z << std::endl;
    std::cout << "Steps are: " << std::endl;
    for(int i = 0; i < (int)whatdo.size(); ++i)
    {
        std::printf("%3d: ", i);
        switch(whatdo[i])
        {
            case action_d1:
            a = dec1(a);
            pvec("Dec 1  to: ", a);
            break;
            case action_m0:
            a = mak0(a);
            pvec("Make 0 to: ", a);
            break;
        }//switch
    }//for
}