I thought that using the sieve of Eratosthenes would slow down the program, but it turned out the opposite.

What is the output for this test?

996 997 754 543
100
42 25 119 17 70
96 293 581 96 391
57 102 888 313 458
55 238 385 15 195
3 576 216 47 117
41 75 849 407 769
87 25 884 319 620
66 94 886 27 552
86 561 377 149 206
90 413 209 74 198
78 32 914 11 840
7 76 814 288 447
72 42 892 370 579
82 42 813 165 677
26 123 561 104 424
38 14 521 154 368
2 120 63 4 38
88 43 887 76 772
71 113 750 88 384
24 78 255 87 138
17 59 862 263 760
44 272 386 117 255
33 368 453 223 330
77 148 846 214 480
76 191 671 219 487
46 305 685 332 436
15 197 356 15 254
37 203 406 74 362
84 14 916 157 603
68 102 287 57 167
98 340 560 81 331
40 7 986 251 728
91 116 791 251 412
92 53 486 13 330
61 8 268 107 217
65 467 304 49 304
22 25 924 250 471
63 430 73 12 38
25 456 462 110 318
80 435 389 102 288
34 673 84 13 59
18 714 7 0 5
32 208 602 7 571
97 189 307 50 232
28 10 836 280 491
56 601 119 42 78
95 36 312 28 229
8 63 821 273 479
35 117 279 126 168
89 195 787 162 421
45 658 59 26 39
74 857 106 18 58
94 269 677 48 445
10 79 636 134 572
31 65 842 214 673
62 294 395 51 308
100 239 197 51 133
20 758 209 10 194
39 26 900 437 721
51 56 712 197 536
6 256 553 93 334
9 210 662 57 598
58 558 371 185 309
47 294 535 222 439
81 265 728 100 713
13 107 464 212 349
27 8 987 137 644
67 43 480 78 355
79 197 644 185 596
99 567 64 10 36
21 62 781 254 502
23 968 5 0 4
69 69 849 92 599
36 66 585 92 382
49 8 747 110 618
73 329 79 9 69
16 366 217 14 161
70 468 527 245 283
93 149 547 252 498
48 35 883 9 797
52 138 611 108 401
60 286 430 104 222
53 119 188 90 152
1 199 505 24 502
5 149 603 73 477
43 325 577 224 399
75 179 709 254 483
29 42 597 212 537
54 585 140 45 105
19 9 680 97 664
11 58 886 281 847
12 223 96 42 93
4 578 228 10 211
14 27 563 94 368
83 67 895 178 778
30 51 882 225 579
50 304 637 315 332
59 99 850 127 762
64 346 19 1 19
85 270 502 185 306

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answer: abbba
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answer: abbbba

Edited by author 25.11.2020 01:48

Edited by author 25.11.2020 01:50

Can someone help how to make C# code faster?
Here is my code:

using System;
using System.Collections.Generic;
class Program
    {
        static int countCut(List<int>[] nods, List<int> uncheckedNodes)
        {
            int next = 0;
            int count = 0;
            do
            {
                count++;
                watchCut(nods, uncheckedNodes, next);
                if (uncheckedNodes.Count > 0)
                    next = uncheckedNodes[0];
                else
                    next = -1;
            } while (next != -1);
            return count;
        }
        static void watchCut(List<int>[] nods, List<int> uncheckedNodes, int node)
        {
            uncheckedNodes.Remove(node);
            for (int i = 0; i < nods[node].Count; i++)
            {
                if (uncheckedNodes.Contains(nods[node][i]))
                    watchCut(nods, uncheckedNodes, nods[node][i]);
            }
        }
        static void Main(string[] args)
        {
            string[] inp_NM = Console.ReadLine().Split(' ');
            int N, M;
            N = Convert.ToInt32(inp_NM[0]);
            M = Convert.ToInt32(inp_NM[1]);
            int[,] threads = new int[M, 2];
            List<int>[] nods = new List<int>[N];
            for (int i = 0; i < N; i++) nods[i] = new List<int>();
            for (int i = 0; i < M; i++)
            {
                string[] inp_thread = Console.ReadLine().Split(' ');
                threads[i, 0] = Convert.ToInt32(inp_thread[0]) - 1;
                threads[i, 1] = Convert.ToInt32(inp_thread[1]) - 1;
                    nods[threads[i, 0]].Add(threads[i, 1]);
                    nods[threads[i, 1]].Add(threads[i, 0]);
            }
            int Q;
            Q = Convert.ToInt32(Console.ReadLine());
            int[] cuts = new int[Q];
            string[] inp_tear = Console.ReadLine().Split(' ');
            for (int i = 0; i < Q; i++)
            {
                cuts[i] = Convert.ToInt32(inp_tear[i]) - 1;
            }
            for (int i = 0; i < Q; i++)
            {
                    nods[threads[cuts[i], 0]].Remove(threads[cuts[i], 1]);
                    nods[threads[cuts[i], 1]].Remove(threads[cuts[i], 0]);
                List<int> uncheckedNodes = new List<int>();
                for (int l = 0; l < N; l++) uncheckedNodes.Add(l);
                Console.Write(countCut(nods, uncheckedNodes)+" ");
            }

        }
    }

Edited by author 24.11.2020 08:00

I had MLE on test 33. I just changed int to short and 1,0 to bool
Sorry if this is too obvious

Edited by author 22.11.2020 16:48

Nuff said

#include <iostream>
#include <string>
#include <vector>
#include <set>

const std::string &solution(const std::vector<std::string> &penguins);

int main() {
    int n;
    std::cin >> n;
    std::cin.clear();
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    std::vector<std::string> penguins;
    penguins.reserve(n);
    for (int i = 0; i < n; ++i) {
        std::string penguin;
        std::getline(std::cin, penguin);
        penguins.emplace_back(std::move(penguin));
    }
    std::cout << solution(penguins) << std::endl;
    return 0;
}

const std::string &solution(const std::vector<std::string> &penguins) {
    std::set<std::string> penguinSet(penguins.begin(), penguins.end());
    auto setIterator = penguinSet.begin();
    std::set<std::string>::iterator mostNumerous;
    int maxCount = 0;
    while (setIterator != penguinSet.end()) {
        int count = 0;
        for (const auto &penguin : penguins) {
            if (*setIterator == penguin) {
                count++;
            }
        }
        if (count > maxCount) {
            maxCount = count;
            mostNumerous = setIterator;
        }
        setIterator++;
    }
    return *mostNumerous;
}

I tested locally and it works...

Problem 1394 "Ships. Version 2" is the same problem as 1115 but has full testset. Problem 1115 has only first 10 tests.

All latest submissions on 1115 were moved to new problem. You can resubmit you solutions to 1115 also if you want.

Problem 1115 was rejudged with 10 tests. But some submissions got WA.

Don't use double or you will suck hard. My formulas are definitely correct (because I got AC), but with double and framework functions like Math.Sqrt I was getting very big inaccuracies (about FEW degrees for angles between tangent and shots). Then I switched to BigInteger and got AC immediately.

Edited by author 19.11.2020 04:59

#include <iostream>
using namespace std;
int main() {
    long long i, j, iDel; long long biggestV = 9999999, biggestDel = 9999999;
    cin >> i >> j;
    if (i == 1) {
        cout << 1;
        return 0;
    }
    else if (i == j) {
        cout << i;
        return 0;
    }
    else if (i + 1 == j) {
        cout << (j % 2 != 0 ? j : i);
        return 0;
    }
    for (long long iV = j % 2 != 0 ? j : j-1; iV >= i; iV -= 2) {
        for (iDel = j / 3 + 1; iDel >= 1; iDel--) {
            if (iV%iDel == 0) {
                if (iDel < biggestDel) {
                    biggestDel = iDel;
                    biggestV = iV;
                }
                break;
            }
        }
        if (iDel == 1) {
            cout << iV;
            return 0;
        }
    }
    cout << biggestV;
}

----
ll l,r;
    cin >> l >> r;
    if(l==1){
        cout << 1;
        return 0;
    }
    if(l == r){
        cout << l;
        return 0;
    }
    ll n = 1e6+2;
    vector<bool> prime(n+1,1);
    prime[0]=prime[1] = 0;
    for( ll i =2; i*i <= n; i++)
    {
        if(prime[i])
        {
            for(ll j = i*i; j <= n; j+=i)
                prime[j]=0;
        }
    }

    for(ll i = r; i >= l; i--){
        if(prime[i])
        {

            cout << i;
            return 0;
        }
    }
    double mx =1e11;
    ll ans = 0;
    for(ll i = r; i >= l; i--){

        if(i % 2 == 0)
            continue;


        double suma = 1;
        for(ll k = 2; k*k <= i; k++){

            if( i % k == 0 ){
                suma += k;
                if(i/k != k){

                    suma += (i/k);
                }
            }
        }

        double q=(suma)/(i);


        if( q < mx){
            mx = q;
            ans = i;
        }

    }
    cout << ans;
    return 0;
----

I used the sieve of Eratosthenes to find prime numbers. If I have not found prime numbers on the interval [l; r], then I iterate over all numbers with [l; r]. I go through the divisors (sqrt (i)). I calculate the minimum. What's wrong? WA 11. Google translator, sorry.

if you wanna get 20 lines solutions, write me on dalydudan@gmail.com

#include <iostream>

using namespace std;



int main(){
int a,b = 0,c = 0,d = 0;
int ocenki[20];
cin » a;

for (int i = 1; i <= a; i++) cin » ocenki[i];
for (int i = 1; i <= a; i++){
if (ocenki[i] == 5){
b++;
}
else if (ocenki[i] == 4){
c++;
}
else if (ocenki[i] == 3){
d++;
}
}
if (d > 0){
cout « "None" « endl;
}
else if (b == a){
cout « "Named" « endl;
}
else if (c > b){
cout « "Common" « endl;
}
else if (c = b){
cout « "High" « endl;
}
return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int m[10]{}, n;
    cin >> n;
    int sum = 0;
    for (int i = 0; i < n; i++)
    {
        cin >> m[i];
        sum += m[i];
    }
    double q;
    q = static_cast<double>(sum) / n;
    if (q == 4)
    {
        cout << "Common";
    }
    if (q > 4.5 && q < 5)
    {
        cout << "High";
    }
    if (q == 5)
    {
        cout << "Named";
    }
    if (q == 3)
    {
        cout << "None";
    }
}

Hi, I'm not sure why I'm failing on test 1. Any ideas?

import sys

def main():
    ans = []
    for line in sys.stdin:
        nums = line.split()
        ans.extend([int(num) ** 0.5 for num in nums if num])
    for root in ans[::-1]:
        print("%.4f" % root)

Anybody know how to decrease mod operations to get more faster solution? I've implemented segment tree, where any node used mod operation to be calculated. I got 0.75s on G++, 0.41s on Clang and 0.25s Visual C++. Maybe I should check if value is overflowed (than mod), but will it be faster?

Can you please give me a test for my code?

How big in compilation time limit? I am getting this error for problem #2107. It is compiling in 1 second on my PC. I don't understand, there is nothing very complicated in my code, just one method with IEnumerable<T> as return value and yield return inside.

 xatosi qayerda bilasizmi?

 var m,n:1..50;
   begin
   read(m,n);
   if odd(m*n)then write('[second]:=]')
   else write('[:=[first]');
  end.