**Update 1.0** : The app is now live here.

Hello Codeforces,

So, I got some requests to predict the future ratings from my fellow coders and I simply didn't ignore it. I have worked a way through which a user can get their future ratings predicted by a piece of code. It was inspired by stefdasca's blog but since I am a bit weak in geometry and graphs so I decided to write a code for it (ignoring the fact that I am weak in coding too).

I have tested it rigourously for like 2-3 times and it did work as the results were satisfactory.

For Eg: The case of 1-gon's profile:

**Screenshot proof**

#### How to get your future ratings:

**Using Web hosted page**

I have made a UI for my app in DHTML. You can give it a try and your review. It is currently deployed here.

**Using C++ code**

**here: 200+ lines**

/*
You need your max_rating, current_rating and last 3 rounds rating changes.
Enter the numbers in this order:
max_rating
current_rating
ratings_change1
ratings_change2
ratings_change3
lucky_number
Sit back and get your rating prediction for as long as you are not satisfied with it.
*/
#include<bits/stdc++.h>
using namespace std;
// #pragma GCC optimize "trapv"
const int SEED_ACCEPTANCE_LT = 10;
const int MULT_ACCEPTANCE_LT = 301;
const int COUNT_PREV_CONTEST_DELTA = 3;
const int MULTIPLIER = 10;
const int UPP_LIM_FOR_MUL = 1000;
const int MAX_RATING_SO_FAR = 3797;
const int MY_FAV_REDUCING_AGENT = -3;
// 12
string title_on_rating[] = {
"Undated",
"Noobie",
"Puppy-lil", "Spicy-list", "Eggs-puff",
"Candyman-Disaster", "Maatsaab", "Entertainment-Mstrbator",
"Grandma's Sister", "Indigenous Gangbastad", "Legendary Grandma",
"Insanity"
};
int ratings_list [] = {
1,
1200, 1400, 1600,
1900, 2100, 2300,
2400, 2600, 3000, MAX_RATING_SO_FAR+1,
10000
};
class Rating {
public:
int maxRating = 0, currRating = 0;
int predictedRating = 0;
int testCases = 1;
int curr_rank = 0;
vector<int> prev_rating_deltas;
Rating (int r1, int r2) {
maxRating = r1, currRating = r2;
predictedRating = r2;
curr_rank = (int)(upper_bound(ratings_list, ratings_list+12, currRating) - ratings_list);
}
void Get_PastRatings() {
prev_rating_deltas.resize(COUNT_PREV_CONTEST_DELTA);
cout << "Enter the ratings delta of past " << COUNT_PREV_CONTEST_DELTA << " contests:\n";
bool rainboy_flag = false;
for (int i = 0; i < COUNT_PREV_CONTEST_DELTA; i++) {
cin >> prev_rating_deltas[i];
rainboy_flag |= (abs(prev_rating_deltas[i]) >= 111);
}
if (rainboy_flag) cout << "\"rainboy delta is detected\"\n";
sort(prev_rating_deltas.begin(), prev_rating_deltas.end());
if (prev_rating_deltas[0] > 0) {
prev_rating_deltas[0] = - prev_rating_deltas[0];
}
if (prev_rating_deltas[COUNT_PREV_CONTEST_DELTA-1] < 0) {
prev_rating_deltas[COUNT_PREV_CONTEST_DELTA-1] = - prev_rating_deltas[COUNT_PREV_CONTEST_DELTA-1];
}
}
void Set_TestCases() {
cout << "Enter your lucky number duh\n";
cin >> testCases;
testCases = (testCases % 9) + 1;
testCases *= MULTIPLIER;
}
void Prediction_Process() {
vector<int> predicted_n_ratings(testCases);
vector<long long> seeds(2);
for (long long &seed: seeds) {
seed = rand() % SEED_ACCEPTANCE_LT + 1;
}
while (seeds[0] == seeds[1]) {
seeds[0] = rand() % SEED_ACCEPTANCE_LT + 1;
}
for (int tc = 0; tc < testCases; tc++) {
int thisRating =
(int)(
(seeds[0] * currRating + seeds[1] * maxRating)
/
(seeds[0] + seeds[1])
);
vector<long long> multipliers_for_prev_rounds(COUNT_PREV_CONTEST_DELTA);
for (long long &mult: multipliers_for_prev_rounds) {
mult = rand() % UPP_LIM_FOR_MUL + 1;
}
sort(multipliers_for_prev_rounds.begin(), multipliers_for_prev_rounds.end());
int medianPos = COUNT_PREV_CONTEST_DELTA / 2;
for (int cc = 0; cc < COUNT_PREV_CONTEST_DELTA; cc++) {
while (llabs(multipliers_for_prev_rounds[cc] - multipliers_for_prev_rounds[medianPos]) > MULT_ACCEPTANCE_LT) {
multipliers_for_prev_rounds[cc] = rand() % UPP_LIM_FOR_MUL + 1;
}
sort(multipliers_for_prev_rounds.begin(), multipliers_for_prev_rounds.end());
}
long long resultantRatingDelta = 0ll, multSum = 0ll;
for (int position = 0; position < COUNT_PREV_CONTEST_DELTA; position++) {
resultantRatingDelta += (multipliers_for_prev_rounds[position] * (long long) prev_rating_deltas[position]);
multSum += multipliers_for_prev_rounds[position];
}
resultantRatingDelta /= multSum;
predicted_n_ratings[tc] = thisRating + (int)resultantRatingDelta;
}
// nearest neighbour like
sort(predicted_n_ratings.begin(), predicted_n_ratings.end());
int median1 = testCases/2, median2 = testCases/2+1;
int group1_mean = predicted_n_ratings[median1], group2_mean = predicted_n_ratings[median2];
int group1_nos = 1, group2_nos = 1;
long long sophisticated_sum1 = 0ll, sophisticated_sum2 = 0ll;
for (int i = 0; i < testCases; i++) {
if (abs(group1_mean - predicted_n_ratings[i]) < abs(group2_mean - predicted_n_ratings[i])) {
if (abs(group1_mean - predicted_n_ratings[i]) < MULT_ACCEPTANCE_LT) {
group1_mean = (int)((long long)group1_mean + predicted_n_ratings[i]) / 2;
sophisticated_sum1 += predicted_n_ratings[i];
group1_nos++;
}
} else {
if (abs(group2_mean - predicted_n_ratings[i]) < MULT_ACCEPTANCE_LT) {
group2_mean = (int)((long long)group2_mean + predicted_n_ratings[i]) / 2;
sophisticated_sum2 += predicted_n_ratings[i];
group2_nos++;
}
}
}
int KNN_like_mean =
(int) (
((long long)(group1_mean) * group1_nos + (long long) (group2_mean) * group2_nos)
/
(long long)(group2_nos + group1_nos)
);
int sophisticated_like_mean =
(int) (((sophisticated_sum1 / group1_nos + sophisticated_sum2 / group2_nos)) / 2
);
// cout << ".\n[KNN_like_mean: " << KNN_like_mean << "] & [sophisticated_like_mean: " << sophisticated_like_mean << "]\n";
if (sophisticated_like_mean > KNN_like_mean) {
swap(sophisticated_like_mean, KNN_like_mean);
}
sort(seeds.begin(), seeds.end());
int KEN_MULTIPLIER = (rand() % MULT_ACCEPTANCE_LT) + MULTIPLIER;
int XEN_MULTIPLIER = (rand() % KEN_MULTIPLIER) / 2 + 1;
predictedRating =
(int)(
((XEN_MULTIPLIER * seeds[0] * sophisticated_like_mean) + (KEN_MULTIPLIER * seeds[1] * KNN_like_mean))
/
(((XEN_MULTIPLIER * seeds[0])) + (KEN_MULTIPLIER * seeds[1]))
);
}
void Analysis() {
cout
<< "Your are currently "
<< title_on_rating[curr_rank]
<< ".\nA little bit of push and you're gonna make it to next level.\n"
<< title_on_rating[curr_rank+1]
<< " is not too far from you. WH!GL!\n";
// cout << curr_rank << ratings_list[curr_rank] << "\n";
}
void Challenge() {
const int maxContestSoFar = 1539;
string url_to_problem = "https://codeforces.com/problemset/problem/";
cout << "\nA random challenge for you is to solve the following problem\n";
cout << url_to_problem << rand() % maxContestSoFar + 1 << "/" << char('A' + (curr_rank + 1) / 2) << "\n";
cout << "(If this link is invalid, the number you entered was not lucky...)\n";
}
};
signed main() {
// random random everywhere.
srand(unsigned(time(0)));
#ifdef LUCTIVUD
// const auto start_time = std::chrono::high_resolution_clock::now();
freopen("/home/luctivud/CPPractice/Zinput.txt", "r", stdin);
freopen("/home/luctivud/CPPractice/Zoutput.txt", "w", stdout);
#endif
// enter currRating and maxRating
int maxR, currR;
cout << "Enter your *max rating* and *current rating* respectively\n";
cin >> maxR >> currR;
// validation of Rating
if (maxR < currR) {
cout << "Your max rating is less than your current rating.. What have you done, dumbass??\n";
return 0;
} else if (maxR > MAX_RATING_SO_FAR) {
cout << "Unfortunately, No one is interested in your insane shit. :P\n";
}
// create rating object
Rating userRating(maxR, currR);
// get past ratings
userRating.Get_PastRatings();
// predict Ratings:
userRating.Set_TestCases();
userRating.Prediction_Process();
// output ratings;
cout << "\n.\n..\n...\n";
cout << "Your *predicted rating* after next few rounds is: " << userRating.predictedRating;// << "\n";
cout << "\n...\n..\n.\n";
userRating.Analysis();
userRating.Challenge();
return 0;
}

- Find the code from here or above
- Run it on your machine and do as it says. You need your max_rating, current_rating and last 3 rounds rating changes.
- The code will ask you for a lucky number. Enter any number.

**Input format:**

max_rating

current_rating

ratings_change1

ratings_change2

ratings_change3

lucky_number

I would encourage some participation from you guys and post in the comments what results you get. Also, if you want me to do a prediction myself I will try my best to be as random as I can.

If the code challenges you to solve a problem don't just run away. Happy coding.

**Future endeavour:**

As I have some knowledge of API handling and Machine Learning as well, so maybe I will work out a real model and train it on some data fetched through Codeforces API and then host it somewhere. I don't know if it will amuse anyone or not but it will be fun task for me :D

P.S. This work is just for fun so don't ask me any proof for it. You can just trust the ratings as it is just a work of statistics and random function with a little bit of K-Means algorithm.

[Some self promotion: Follow me on github and star this repo if you find it helpful and all of the code related to this blog is in this separate repository.]

Why does the prediction depend on the choice of a lucky number?I tried multiple lucky numbers and it showed different results

That's why it's called "lucky" number

But the differences are huge among the predictions

Actually the result is generated through randomisation and KMeansLike algorithm so you will get different results every time. Lucky number is just a random number to decide the number of intermediate predicted ratings to be generated. All of those results will be in a specific range which corresponds to the predicted rating range and predicted rating is the most probable one of them.

I wonder, what will it predict for cheaters smoll pp

Your program just give me a bunch of string problems for practice!

I like it!

I am thinking which rating it will predict for my fellow friend rainboy :3

Here you goA rainboy detection mechanism has been employed.

It predicted my future rating to be 2214. Would love that tbh, haven't crossed 2200 for a while.

Amazing work out there! I'm looking forward for future developments.

P.S: it looks like I should take contests again since my predicted rating is bigger than my current rating :D

This is what it predicted for me:

SpoilerAnd this is the problem I got told to solve.

What is Entertainment Mstrbator?

International Master I guess

"rainboy delta is detected"

Interesting... Seems like I will be a Future GM... Made my day

I have also created a similar service! Go to random.org, put "500" under Min, "4000" under Max and press the "generate" button. This will be my prediction of your rating after 5 years.

I'll be grey after 5 years : |

POV: I used it to find my lucky number.

This actually works :} It predicted that within few contests, I'll be a pupil and my rating will be 1248 or something (Don't remember exactly) Now I am a pupil :}