Depth First Search in C++

Published on 28 April 2022 (Updated: 27 November 2022)

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:

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

Note: The solution shown above is the current solution in the Sample Programs repository as of Oct 10 2022 16:05:09. The solution was first committed on Oct 03 2022 22:15:16. As a result, documentation below may be outdated.

How to Implement the Solution

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How to Run the Solution

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