My Roadmap

My Setups - cpp java python 🔥

C++

tip

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

typedef vector <int> vi;
typedef pair< int ,int > pii;
#define endl "\n"
#define sd(val) scanf("%d",&val)
#define ss(val) scanf("%s",&val)
#define sl(val) scanf("%lld",&val)
#define debug(val) printf("check%d\n",val)
#define all(v) v.begin(),v.end()
#define PB push_back
#define MP make_pair
#define FF first
#define SS second
#define ll long long
#define MOD 1000000007
#define clr(val) memset(val,0,sizeof(val))
#define what_is(x) cerr << #x << " is " << x << endl;
#define FIO ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);


int main()
{

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);

    return 0;
}

• Use using instead of typedef, for example using ll = long long;.

• Use auto to increase readability and decrease code size.

• Use ios::sync_with_stdio(false); and cin.tie(nullptr); for faster Input/Output using cin/cout.

• Use builtin functions starting with __builtin.

• GCD and LCM are available in ***C++17*** under `gcd` and `lcm`.

• Use C++11 for-each style for loops for (auto& elem : vec).

• Use C++17 binding style like for (auto& [key, val] : dic) and auto [x, y] = myPoint;

• Use C++17 template argument deduction pair p{1, 2.5}; instead of pair<int, double> p{1, 2.5};.

• If you have a lot of nested loops and conditions, refactor! You probably should be using functions.

• Never use goto! But be brave enough to use goto when you want to break from several nested loops (in case you just can't refactor it)!

• Some websites like codeforces use the flag -DONLINE_JUDGE to compile your code, this means that you can remove your cerrs or your debug functions automatically or redirect input/output to file instead of stdin/stdout, etc.

Java

import java.io.*;
import java.util.*;

public class Main {
    //BeginCodeSnip{Kattio}
    static class Kattio extends PrintWriter {
        private BufferedReader r;
        private StringTokenizer st;

        // standard input
        public Kattio() { this(System.in, System.out); }
        public Kattio(InputStream i, OutputStream o) {
            super(o);
            r = new BufferedReader(new InputStreamReader(i));
        }
        // USACO-style file input
        public Kattio(String problemName) throws IOException {
            super(new FileWriter(problemName + ".out"));
            r = new BufferedReader(new FileReader(problemName + ".in"));
        }

        // returns null if no more input
        public String next() {
            try {
                while (st == null || !st.hasMoreTokens())
                    st = new StringTokenizer(r.readLine());
                return st.nextToken();
            } catch (Exception e) { }
            return null;
        }

        public int nextInt() { return Integer.parseInt(next()); }
        public double nextDouble() { return Double.parseDouble(next()); }
        public long nextLong() { return Long.parseLong(next()); }
    }
    //EndCodeSnip
    // add methods
    // add methods

    public static void main(String[] args) {
        Kattio io = new Kattio();
        // long x = io.nextLong(); String str = io.next(); int a = io.nextInt();
        // io.println(x);   /* For System.out.println() */ or // io.print(x);


        // Code


        io.close(); // make sure to include this line -- closes io and flushes the output
    }
}

---

info

Explanatory Template same as above

/** Simple yet moderately fast I/O routines.
 *
 * Example usage:
 *
 * Kattio io = new Kattio();
 *
 * while (io.hasMoreTokens()) {
 *    int n = io.nextInt();
 *    double d = io.nextDouble();
 *    double ans = d*n;
 *
 *    io.println("Answer: " + ans);
 * }
 *
 * io.close();
 *
 *
 * Some notes:
 *
 * - When done, you should always do io.close() or io.flush() on the
 *   Kattio-instance, otherwise, you may lose output.
 *
 * - The nextInt(), nextDouble(), and nextLong() methods will throw an
 *   exception if there is no more data in the input, so it is generally
 *   a good idea to use hasMoreTokens() to check for end-of-file.
 *
 * @author: Kattis
 */

import java.util.*;
import java.io.*;

class Kattio extends PrintWriter {
    private BufferedReader r;
    private StringTokenizer st = new StringTokenizer("");
    private String token;

    // standard input
    public Kattio() {
        this(System.in, System.out);
    }

    public Kattio(InputStream i, OutputStream o) {
        super(o);
        r = new BufferedReader(new InputStreamReader(i));
    }

    // USACO-style file input
    public Kattio(String problemName) throws IOException {
        super(new FileWriter(problemName + ".out"));
        r = new BufferedReader(new FileReader(problemName + ".in"));
    }

    private String peek() {
        if (token == null)
            try {
                while (!st.hasMoreTokens()) {
                    String line = r.readLine();
                    if (line == null)
                        return null;
                    st = new StringTokenizer(line);
                }
                token = st.nextToken();
            } catch (IOException e) {
            }
        return token;
    }

    public boolean hasMoreTokens() {
        return peek() != null;
    }

    private String next() {
        String ans = peek();
        token = null;
        return ans;
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }

    public long nextLong() {
        return Long.parseLong(next());
    }
}

public class Main {
    static Kattio io = new Kattio();

    public static void main(String[] args) {
        int a = io.nextInt();
        int b = io.nextInt();
        int c = io.nextInt();
        io.print("sum is ");
        io.println(a + b + c);
        io.close(); // make sure to include this line -- closes io and flushes the output
    }
}

Python

def hello_world():
  print 'Hello, world!'

---

Debugging C++ Template

#include<bits/stdc++.h>

using namespace std;

#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define MOD 1000000007
#define MOD1 998244353
#define INF 1e18
#define nline "\n"
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}

template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

int main() {
#ifndef ONLINE_JUDGE
    freopen("Error.txt", "w", stderr);
#endif

    // Code

}

---

Visualisations

• https://www.cs.usfca.edu/~galles/visualization/Algorithms.html
  
• https://visualgo.net/en

---

Cpp Documentations:

tip

• https://www.cplusplus.com/reference/ ~ Beginner Friendly
• https://en.cppreference.com/w/cpp/header ~ Better Advanced
• https://devdocs.io/cpp/ ~ Based on cppreference.com

• https://docs.microsoft.com/en-us/cpp/standard-library/cpp-standard-library-header-files?view=msvc-160
• https://www.learncpp.com/
• https://github.com/aitjcize/cppman ~ Offline Documentation for Terminal
• https://www.boost.org/ ~ Boost C++

---

Java Documentations:

tip

• Java SE 14 https://docs.oracle.com/en/java/javase/14/docs/api/java.base/module-summary.html
• Java SE 15 https://docs.oracle.com/en/java/javase/15/docs/api/java.base/module-summary.html
• Java SE 16 https://docs.oracle.com/en/java/javase/16/docs/api/java.base/module-summary.html
• Java 8 Technotes https://docs.oracle.com/javase/8/docs/technotes/guides/
• Java 8 Tutorials https://docs.oracle.com/javase/tutorial/

---

Learning DSA

https://codeforces.com/blog/entry/57282

Resources I am Following:

• Apna college DSA
• Coding Blogs Interview Prep
• Coding Blogs Interview Prep
• Coding Ninja Competitive
• Coding Blocks Competitive
• CodeForces Edu: https://codeforces.com/edu/course/2
• https://www.codechef.com/cptutorials
• https://www.codechef.com/getting-started
• https://www.codechef.com/ioi/basics

---

Other Resources

• Codeforces Blogs
• InterviewBit Blogs

Must Use Resources to Learn:

1. java acad__
2. HackerEarth Notes / Code Monk
3. InterviewBit Materials
4. Educative-> Grokking the Coding InterviewBit
5. CP- Algorithms
6. GeeksforGeeks
7. TopCoder Blogs
8. CodeForces Blogs
9. CodeChef Resources
10. algoExperts
11. Atcoder Begineer and Regular Editorials

---

TopicWise:

Dynamic Programming

• https://www.reddit.com/r/cscareerquestions/comments/fqzj73/is_the_grokking_dynamic_programming_patterns_from/

• https://leetcode.com/discuss/general-discussion/458695/dynamic-programming-patterns

• https://emre.me/categories/#coding-patterns

• https://www.topcoder.com/community/competitive-programming/tutorials/dynamic-programming-from-novice-to-advanced/

• https://www.topcoder.com/thrive/articles/Dynamic%20Programming:%20From%20Novice%20to%20Advanced

• https://leetcode.com/discuss/general-discussion/458695/dynamic-programming-patterns/439810

• https://leetcode.com/discuss/study-guide/1437879/dynamic-programming-patterns

• https://leetcode.com/discuss/general-discussion/458695/dynamic-programming-patterns

• https://leetcode.com/discuss/general-discussion/458695/dynamic-programming-patterns/439810

• https://leetcode.com/discuss/study-guide/1437879/dynamic-programming-patterns

• https://leetcode.com/discuss/general-discussion/458695/dynamic-programming-patterns

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Guides:

1. The Guide
2. hSkill Roadmap
3. Codechef Certificate: https://www.codechef.com/certification/data-structures-and-algorithms/prepare

• Resources Links:

1. https://techprep.org/ by Facebook

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Websites to prepare for Aptitude/ Reasoning:

1. FreshersWorld
2. Puzzlefry
3. IndiaBIX
4. AmbitionBox
5. Fresherslive

...

• Linkedin
• Internshala
• Careers
• U dg

caution

Caution Section

Hackathons

• Major League Hacking
• DevPost
• Hackathons International
• Hackaday
• DevFolio
• Hack Club
• HackaList
• AngelHack
• Hackathon IO
• https://www.githubhackathon.com/#hackathon
• https://github.com/github/hackathons

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