Depth First Search in C++

Welcome to the Depth First Search in C++ page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

#include <bits/stdc++.h>
using namespace std;

const int N = 3e5 + 10;
bool vis[N];
vector<int> g[N];

void handle_error()
{
    cout << "Usage: please provide a tree in an adjacency matrix form (\"0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0\") together with a list of vertex values (\"1, 3, 5, 2, 4\") and the integer to find (\"4\")\n";
    exit(0);
}

int check(string s)
{
    int x1 = 0, x2 = (int)s.size() - 1;

    for (int i = 0; i < s.size(); i++)
    {
        if (s[i] != ' ')
        {
            x1 = i;
            break;
        }
    }

    for (int i = (int)s.size() - 1; i >= x1; i--)
    {
        if (s[i] != ' ')
        {
            x2 = i;
            break;
        }
    }

    for (int i = x1; i <= x2; i++)
    {
        if (s[i] == ' ')
        {
            handle_error();
        }
    }

    return stoi(s);
}

vector<int> convert(string s)
{

    if (s.size() == 0)
    {
        handle_error();
    }
    vector<int> v;
    string num = "";
    for (int i = 0; i < s.size(); i++)
    {
        if (((int)s[i] >= 48 && (int)s[i] <= 57) || s[i] == ' ')
        {
            num += s[i];
        }
        else if (s[i] == ',')
        {
            v.push_back(check(num));
            num = "";
        }
    }

    if (num.size() > 0)
    {
        v.push_back(check(num));
    }

    return v;
}

void dfs(int root)
{

    vis[root] = 1;

    for (auto child : g[root])
    {

        if (vis[child])
            continue;

        dfs(child);
        vis[child] = 1;
    }
}

int main(int argc, char *argv[])
{
    if (argc <= 1)
        handle_error();

    vector<int> bin = convert(argv[1]), nodes = convert(argv[2]), t = convert(argv[3]);
    if (bin.size() == 0 || nodes.size() == 0 || t.size() == 0)
        handle_error();

    int sz = (int)nodes.size();
    int k = 0;
    int f = sqrt(bin.size());
    if (sz != f)
        handle_error();
    for (int i = 0; i < bin.size(); i += sz)
    {
        for (int j = i; j < i + sz; j++)
        {
            if (bin[j] == 1)
            {
                g[nodes[j - sz * k]].push_back(nodes[k]);
                g[nodes[k]].push_back(nodes[j - sz * k]);
            }
        }
        k++;
    }

    int src = nodes[0];
    dfs(src);
    if (vis[t[0]])
        cout << "true"
             << "\n";
    else
        cout << "false"
             << "\n";
}

Depth First Search in C++ was written by:

• Ajay Maheshwari
• Jeremy Grifski

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

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How to Run the Solution

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