Sorry in advance, but some variable names and such have strange names, as I am not a native English speaker, I am also pretty new to programming.
So, I was doing a project with graphs topology sorting and similar, but I can't get DFS to work, I know that I am probably losing data because of usage of pointers in there(?), but I won't be using this adjacency list in my program any further anyway. The problem is just to get right result which in this case is when the vertex was entered (d[]) and left (f[]) but while in recursion my pointers go crazy, sometimes when I go back in recurrence (and apparently nothing else happens), I think at least because it's the first time I am using debugging function. I am sitting at this for like 8 hours already (not my first problem, but I managed to solve some, that's why code looks so ugly), and I was sitting with this debugger and didn't make any progress in over an hour, so I decided to ask, my first time using this website, I hope you can help me, and when I am a bit better I will definitely return the favor, here's the code:
#include <iostream>
#include <cstdlib>
#include <time.h>
struct m_sasiedztwa
{
int s;
int** m;
m_sasiedztwa(int a,float b) : s(a)
{
m = new int*[s];
for(int i = 0; i < s; ++i) m[i] = new int[s];
for(int j=0; j<s; ++j)
for(int k=0; k<s; ++k) if(j!=k) m[j][k]=((rand()%100)>(100*b))? 0 : 1; else m[j][k]=0;
}
~m_sasiedztwa()
{
delete[] m;
}
};
struct lista
{
int key;
lista *next;
};
struct l_nast
{
int s;
lista** arr;
l_nast(int** m, int a) : s(a)
{
lista *curr,*prev;
arr = new lista*[s];
for(int i=0;i<s;++i)
{
arr[i] = new lista;
curr = arr[i];
prev=curr;
prev->key=-1;
for(int j=0;j<s;++j)
{
if(m[i][j]==1) {curr->next= new lista;curr->key=j;prev=curr;curr=curr->next;}
}
prev->next=nullptr;
}
}
~l_nast() {delete[] arr;}
};
//Here is the issue
bool *Nowy;
int c;
int* d,*f;
void DFS(int j,l_nast l_a)
{
Nowy[j]=false;
d[j]=c++;
std::cout<<"Am I here yet..."<<j<<" "<<c<<std::endl;
while((l_a.arr[j]!=nullptr)&&(l_a.arr[j]->key!=-1))
{
std::cout<<"checking "<<(l_a.arr[j]->key)<<"...\n";
if(Nowy[l_a.arr[j]->key])
{
DFS(l_a.arr[j]->key,l_a);
}
if(l_a.arr[j]->next!=nullptr) //And I think this may be the problem, but I honestly don't know
l_a.arr[j]=l_a.arr[j]->next;
else break;
}
f[j]=c++;std::cout<<"Yohoo!"<<j<<" "<<c<<std::endl;
}
//Untill there
using namespace std;
int main()
{
srand (time(NULL));
for(int q=5; q<6; q+=5)
{
m_sasiedztwa a = m_sasiedztwa(q, 0.2);
m_sasiedztwa b = m_sasiedztwa(q, 0.4);
l_nast l_a = l_nast(a.m,q);
l_nast l_b = l_nast(b.m,q);
/*
for(int i=0; i<q; ++i)
{
for(int j=0; j<q; ++j)
{
cout << a.m[i][j] << " ";
}
cout<<endl;
}
cout<<endl;
*/
Nowy = new bool [q];
d = new int [q];
f = new int [q];
c=0;
for (int i = 0; i < q; i++)
Nowy[i] = true;
/*for(int qq=0;qq<q;qq++)
while((l_a.arr[qq]!=nullptr))
{
cout<<l_a.arr[qq]->key<<endl;
l_a.arr[qq]=l_a.arr[qq]->next;
}
*/
for(int j=0;j<q;j++)
{
if(Nowy[j]) DFS(j,l_a);
}
a.~m_sasiedztwa();
b.~m_sasiedztwa();
l_a.~l_nast();
l_b.~l_nast();
}
return 0;
}
As I said it's not pretty, sorry for troubling you, again what I need help with is to get function DFS to properly result with d[] which is a table if integers which indicate when the vertex was visited, and f[] - table when the vertex was taken from the stack, just ordering 1,2,3..., the problem is - it breaks in the middle, sometimes it does like 7/10 sometimes just 2/10 and it breaks, of course, it will have to work for bigger graphs as well. The pointers are lost and it tries to check Nowy[some big number there] and program crashes.
So, I used struct badly and made many mistakes, thanks to some comments I decided to use vector of vectors for adj matrix and vector of forward_list for adj list Here is what changed m_sasiedztwa struct
struct m_sasiedztwa
{
int s;
std::vector<std::vector<int>> m;
m_sasiedztwa(int a,float b) : s(a), m(s, std::vector<int>(s,0))
{
for(int j=0; j<s; ++j)
for(int k=0; k<s; ++k)
if(j!=k)
m[j][k]=((rand()%100)>(100*b))? 0 : 1;
}
};
l_nast struct:
struct l_nast
{
int s;
std::vector<std::forward_list<int>> arr;
l_nast(std::vector<std::vector<int>> m, int a) : s(a), arr(s)
{
for(int i=0;i<s;++i)
{
auto it = arr[i].before_begin();
for(int j=0;j<s;++j)
{
if(m[i][j]==1) {it = arr[i].emplace_after(it,j);}
}
}
}
};
and the DFS:
void DFS(int j,l_nast l_a)
{
Nowy[j]=false;
d[j]=c++;
std::cout<<"Visiting "<<j<<"as "<<c<<std::endl;
auto x=l_a.arr[j].begin();
for(auto& x: l_a.arr[j])
{
if(Nowy[x])
{
DFS(x,l_a);
}
}
f[j]=c++;std::cout<<"Leaving "<<j<<"as "<<c<<std::endl;
}