How are Solutions Executed in an OJ?, project of some sort. First thing that came to my mind is to build a small cute
OJ. I'm aware that we, So I did a light research yesterday about what I might need to learn to build
it. The first obvious
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Results
1.
How are Solutions Executed in an OJ? Hello Codeforces!
It's been long since I last had the fun of any serious programming(being all night awake with loud music on headphones and lots of snacks infront) due to admission studies. I'm missing it a lot. So after the exams are done I wish to improve MathMash a lot and also start a pet project of some sort. First thing that came to my mind is to build a small cute OJ. I'm aware that we have plenty of OJs already and they are more than enough helpful. So this project won't be of much use to anyone. But it'll be fun to design and build an entire OJ from scratch and also learn lots of new stuff along the way.
So I did a light research yesterday about what I might need to learn to build it. The first obvious thing needed is of course a way to execute submitted codes. I tried to go with the easiest option first: Using some third-party service/api so that I can give them the code and receive the output. But there doesn't seem to be any free option of this kind. Ideone used to p...
2.
Light OJ 1269 — Consecutive Sum Cany anyone give me some hints how can i solve the problem using segment tree?
**Problem Link:** [Consecutive Sum](http://lightoj.com/volume_showproblem.php?problem=1269)
**Problem Description:**
Little Jimmy is learning how to add integers. As in decimal the digits are 0 to 9, it makes a bit hard for him to understand the summation of all pair of digits. Since addition of numbers requires the knowledge of adding digits. So, his mother gave him a software that can convert a decimal integer to its binary and a binary to its corresponding decimal. So, Jimmy's idea is to convert the numbers into binaries, and then he adds them and turns the result back to decimal using the software. It's easy to add in binary, since you only need to know how to add (0, 0), (0, 1), (1, 0), (1, 1). Jimmy doesn't have the idea of carry operation, so he thinks that
~~~~~
1 + 1 = 0
1 + 0 = 1
0 + 1 = 1
0 + 0 = 0
~~~~~
Using these operations, he adds the numbers in binary. So, according to hi...
Light OJ 1269 — Consecutive Sum
3.
Need Help on Problem Light-OJ 1429 — Assassin`s Creed (II) I Have tried this problem for long time but not getting accepted solution.
My idea was:
1) Find Strongly Connected Components.
2) Form a DAG.
3) Run topsort on the DAG.
4) A DFS for number of assasin.
But I am getting continuously WA.
**Problem:**
Ezio needs to kill N targets located in N different cities. The cities are connected by some one way roads. As time is short, Ezio can send a massage along with the map to the assassin's bureau to send some assassins who will start visiting cities and killing the targets. An assassin can start from any city, he may visit any city multiple times even the cities that are already visited by other assassins. Now Ezio wants to find the minimum number of assassins needed to kill all the targets.
**Input**
Input starts with an integer T (≤ 70), denoting the number of test cases.
Each case starts with a blank line. Next line contains two integers N (1 ≤ N ≤ 1000) and M (0 ≤ M ≤ 10000), where N denotes the number of citie...
Need Help on Problem Light-OJ 1429 — Assassin`s Creed (II)
4.
Help to improve my way of practice I am doing CF for about one year. But still , I am newbie here. It is not like that A,B seem so hard.I become so nervous during cf round .
During contest suddenly my head becomes blank and I feel like I am caged and so I cannot think further . As a result , I cannot come to solution for any problem further .
It is destroying my confidence level day by day.
And during practice , I do not follow any particular strategy . Because I get confused what to do! Sometimes I solve from cf according to junior practise sheet(provided by an arabian coach may be, found online), sometimes I solve from light oj/uva and sometimes I learn Algorithms . Algorithms I know -
Bfs,dfs,mst,dijkstra,nim,trie,kmp,binary search,matrix exponentiation, dp(coin change,knapsack,LCS,LIS,edit distance)
I have solved average 9 to 10 problems on these topics.
I know more algorithms like segment tree,LCA etc on which I have just solved 2 to 3 problems.
I will be grateful if anyone will share...
solve from light oj/uva and sometimes I learn Algorithms . Algorithms I know -
Bfs,dfs,mst,dijkstra, , found online), sometimes I solve from light oj/uva and sometimes I learn
Algorithms . Algorithms I
5.
Need Help on Light Oj problem 1233! I need help on Light Oj problem 1233(Coin Change (III)).
<spoiler summary="Problem Link">
https://vjudge.net/problem/LightOJ-1233
</spoiler>
I came up with a solution of O(T*N*M*C[i]). Here is my idea: Let dp[i][j] is true if we can make value j using first i coins. So, dp[i][j]=true if dp[i-1][j-k*x] is true for (0<=k<=c[i-1]) where i>0, x is the current coin and (j-k*s>=0). Initially dp[0][0]=true since we can make 0 using 0 coins. Final result will be sum of dp[n][i] where (1<=i<=m).
<spoiler summary="My Submission">
https://paste.ubuntu.com/p/7MkG74mkgk/
</spoiler>
. But this solution is slow. How to make it faster? How to solve this problem using O(T*N*M) time complexity?
Need Help on Light Oj problem 1233!, I need help on Light Oj problem 1233(Coin Change (III)).
6.
Please gebug my program , I can't find bugs !!! Hello everybody , I have tried a lot to solve the light oj 1087 — Diablo problem .
problem link : http://www.lightoj.com/volume_showproblem.php?problem=1087
My test sample output is not matching , I have tried a lot , I am a noob , please help me to debug my code . Why does it occur ??
my code : https://paste.ubuntu.com/26080511/
Please help me , Downvote ?? It's okay . But please help me ..................
Hello everybody , I have tried a lot to solve the light oj 1087 — Diablo
problem .
7.
Help me please Hello everybody , please help me , i was solving problems in light oj , "curious Robin Hood" and getting wrong answer.
problem link : http://lightoj.com/volume_showproblem.php?problem=1112
code link : https://paste.ubuntu.com/25753376/
i am a beginner and i recently learned a bit about segment tree , i used segment tree in this solution , but i can't find my faults , can anyone please help me ?
Hello everybody , please help me , i was solving problems in light oj ,
"curious Robin Hood" and
8.
Light OJ 1248 Help in this [problem](http://lightoj.com/volume_showproblem.php?problem=1248)
My Think: Say E(x) is the expected value when we see x sides of dice.
E(x) = (x / n) (1 + E(x)) + ((n — x) / n) (1 + E(x + 1))
where at this time, the probability of getting the old side of dice which is already done is (x / n) and renaming are (n — x) which need to see at least once, probability of that (n — x) / n.
Thanks in advance.
Light OJ 1248
9.
Light OJ 1205 Any idea on How solve this palindrome problem?? Is this one a dynamic programming problem??!!
Light OJ 1205.
https://lightoj.com/problem/palindromic-numbers
Light OJ 1205
10.
Rooks I am trying to solve the problem for a long time but still didn't get any idea how to solve it. It would be great if you help me to solve it.
Problem Link : https://vjudge.net/contest/332542#problem/A
Since the contest is ended that's why I share the vjudge link because I think everyone has not a light oj id and this problem is from light online judge(loj).
Thanks in advance :)
sorry for my poor english. :)
a light oj id and this problem is from light online judge(loj). Thanks in
advance :) sorry for my, light oj id and this problem is from light online judge(loj). Thanks in advance
:) sorry for my poor
11.
Light OJ 1392 — Multi Round Matches Problem link: [Light OJ 1392.](http://lightoj.com/volume_showproblem.php?problem=1392)
Please give it a read. If I understood correctly, given $R,T,N$, it asks to find number of pairs $(r,t)$ with $0\le r < R,0\le t < T$ such that there exists integers $a_{1},...,a_{r}$ whose sum is $t$ and each of the numbers $a_i$ is between $1$ and $N$ (inclusive). Constraints are $1\le R\le 10^8,1\le T\le 4*10^8,2\le N\le 20$.
But then for a fixed $r$, all $t$ between $r$ and $Nr$ should be reachable (others are not reachable because each of the $r$ variables is at least $1$ and at most $N$). So I ran a brute force (to check), but they don't match the sample.
Code: [here.](http://ideone.com/PmlDzn)
Interesting enough, the output of the brute force for each sample is exactly $26$ more than actual answer. Where did I go wrong?
Light OJ 1392 — Multi Round Matches, Problem link: [Light OJ
1392.](http://lightoj.com/volume_showproblem.php?problem=1392)
12.
Summation of all pair of number's LCM(Lowest Common Multiple) Given a number N we have to find the summation of all possible LCM(i,j) where i <= j <= N.
Constraints: N<=10^6 and total test case <= 10^5
Problem Link : [Light OJ 1375](http://lightoj.com:81/volume/problem/1375)
. Constraints: N<=10^6 and total test case <= 10^5 Problem Link : [Light OJ
1375](http://lightoj.com:81, Problem Link : [Light OJ 1375](http://lightoj.com:81/volume/problem/1375)
13.
Help in Convex Hull Problem Hello Everyone,
I have been trying to solve this problem "Light Oj — 1313" for so long but could not find any solution.
I can understand convex hull and point in polygon part than I got stuck every time. Can anybody tell me how to solve this problem. Thank you .
problem link : (http://www.aichengxu.com/other/3595766.htm)
I am giving this link because you must have an account to open the main problem.
Hello Everyone, I have been trying to solve this problem "Light Oj — 1313" for
so long but
14.
Help in Light OJ 1301 In Light OJ[1301](http://lightoj.com/volume_showproblem.php?problem=1301) what is the simplest idea to solve it ? My code [here](https://ideone.com/WOUF2b) . It got TLE . I know the approach is wrong but can't figure it out. Please anyone help.
Help in Light OJ 1301, In Light OJ[1301](http://lightoj.com/volume_showproblem.php?problem=1301) what
is the simplest
15.
Light Oj : 1155 — Power Transmission , Flow Problem [Problem Link](http://www.lightoj.com/volume_showproblem.php?problem=1155)
My approach for solving this problem is to form a new source from given multiple sources based on the capacity of the sources. And also for the given multiple sink, form a new sink whose edge's weight is the capacity of the given (multiple) sinks. My default source and sink is 0 and 250.
In case of a node which is not source or sink, I connect a new node with that given node( adding 120 ) having a edge weights the capacity of the given node.
Then I run Flow.
[My code](http://ideone.com/yBO69l) gives Runtime error. I would be very happy with some help.
UPD:ACed it. Got some problem in implementation.
Light Oj : 1155 — Power Transmission , Flow Problem
16.
I want to learn iterative dp Here is a problem I had been trying in Light Oj.
Problem link: http://paste.ubuntu.com/11060539/
(Since Light OJ need a user id to access)
I could solve it recursively:
My solution: http://paste.ubuntu.com/11060583/
Now I want to solve it iteratively. But I am failing to do it. Please explain me how I can do this in iterative process in two dimension array like, int dp[102][10002]:: dp[n][k];
In some code I see to act like this:
for(int i=0;i<=n;i++) dp[i][0]=1;
why does it fill,fill dp[i][0]?
Please I need to learn this . I am trying but failing.
Thanks in advance.
Here is a problem I had been trying in Light Oj., Problem link: http://paste.ubuntu.com/11060539/ (Since Light OJ need a user id
to access)
17.
Can AnyOne Give me Some idea how to solve this Problem? I am new to DP Problem. (Light Oj -1031- Easy Game) You are playing a two player game. Initially there are n integer numbers in an array and player A and B get chance to take them alternatively. Each player can take one or more numbers from the left or right end of the array but cannot take from both ends at a time. He can take as many consecutive numbers as he wants during his time. The game ends when all numbers are taken from the array by the players. The point of each player is calculated by the summation of the numbers, which he has taken. Each player tries to achieve more points from other. If both players play optimally and player A starts the game then how much more point can player A get than player B?
Input
Input starts with an integer T (≤ 100), denoting the number of test cases.
Each case contains a blank line and an integer N (1 ≤ N ≤ 100) denoting the size of the array. The next line contains N space separated integers. You may assume that no number will contain more than 4 digits.
Output
For each test case,...
Can AnyOne Give me Some idea how to solve this Problem? I am new to DP Problem.
(Light Oj -1031
18.
Light OJ — Making Huge Palindromes VERDICT: Wrong Answer....the problem is about to find the length of the smallest palindrome that can be formed by adding some additional character at it end(possibly zero).
i used prefix function of original given string comparing with its reverse to find out the largest suffix in the original string that is a prefix of its reverse that means palindromes.For several test case i found it working but verdict is "Wrong Answwer".Can anyone help me with test case or tell me reason why it may not work in this case.
~~~~~
int prefix_function(string original, string rev)
{
string text = rev + '#' + original;
int n = text.size();
int m = original.size();
vector<int>lps(n);
for (int i = m + 1, j = 0; i < n; )
{
if (text[i] == text[j])
{
lps[i] = j + 1;
j++;
i++;
}
else
{
if (j != 0) j = lps[j - 1];
else lps[i] = 0, i++;
}
}
return lps[n - 1];
}
~~~~~
Light OJ — Making Huge Palindromes
19.
Getting TLE , my printAll function may be slow , please give me tips Hello codeforces , I tried to solve [Light Oj : 1110 — An Easy LCS] (http://www.lightoj.com/volume_showproblem.php?problem=1110)
but getting TLE , here is My [code](https://paste.ubuntu.com/p/8zK7vwVsR6/) please help me to reduce my runtime :) thanks for advance :)
Hello codeforces , I tried to solve [Light Oj : 1110 — An Easy LCS]
(http://www.lightoj.com
20.
Binary Index Tree or Segment Tree Problem Problem: [Light OJ — Lining up Students](http://www.lightoj.com/volume_showproblem.php?problem=1187)
can anyone give me any idea
how can i solve this problem with Binary Index Tree or Segment Tree???
Problem: [Light OJ — Lining up
Students](http://www.lightoj.com/volume_showproblem.php
21.
Light OJ 1129 — Consistency Checker I am getting Run Time Error of Light OJ 1129 — Consistency Checker( http://lightoj.com/volume_showproblem.php?problem=1129 ) Problem . Here is my code
~~~~~
Removed After AC
~~~~~
Anyone Please help why Run time Error
Light OJ 1129 — Consistency Checker
22.
DP Problem Help ( Ordered Flips , Light Oj - 1351 ) Can anyone please tell me the process how to solve [this](http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=27059) problem . Thanx in advance :)
DP Problem Help ( Ordered Flips , Light Oj - 1351 )
23.
[Data Structure Problem] Light OJ 1424 — New Land Problem Link: http://lightoj.com/volume_showproblem.php?problem=1424
Solution Link: https://ideone.com/2eUIav
Verdict: TLE
Solution Approach: Trying out all possible row combinations and for each row combination finding the maximum area using binary search
Someone please help me out how can I optimize my solution.
[Data Structure Problem] Light OJ 1424 — New Land
24.
Dynamic Programming + Binary Search (Light OJ 1180 – Software Company) Problem Link: http://lightoj.com/volume_showproblem.php?problem=1180&language=english&type=pdf
I have read in a blog that this particular problem involves dynamic programming with binary search. Someone kind enough please provide me an explanation on how to solve this problem using the mentioned topics.
Dynamic Programming + Binary Search (Light OJ 1180 – Software Company)
25.
Weird run-time error in java Hello Codeforces!
Can anybody please explain why this code is giving run-time error on codeforces? This solution is accepted in the actual OJ where the contest took place.
Here is the contest link-
https://codeforces.me/gym/102141
Problem no is **G**.
Here is my code-
https://ideone.com/xEqXuc
Could it be a reason that the testcases are not given as standard input output rather as a file? Although there seems to be no problem when using C++. So I can't be sure of what's going on here! Someone please shed some light here.
codeforces? This solution is accepted in the actual OJ where the contest took
place. Here is the contest
26.
Inclusion - Exclusion problem from Light OJ Problem Name: Ray Gun
Problem Link: http://lightoj.com:81/volume/problem/1144
Any hints for the solution will be really appreciated.
Inclusion - Exclusion problem from Light OJ
27.
get wrong answer light oj 1205 no problem:http://www.lightoj.com/volume_showproblem.php?problem=1205
i have get wrong answer....but i don't understand what am i wrong..please help anyone...
my code is:https://ideone.com/UqS9XD
light oj 1205 no
problem:http://www.lightoj.com/volume_showproblem.php?problem=1205 i have get
28.
LIGHT OJ love calculator DP problem i am trying to solve this problems for days but couldn't reach any solution....1st part is about lcs but how can i solve the 2nd part
http://lightoj.com/volume_showproblem.php?problem=1013
LIGHT OJ love calculator DP problem
29.
BIT problem from Light OJ (1097 - Lucky Number) Problem ID: 1097
Problem Name: Lucky Number
Problem Link: http://lightoj.com/volume_showproblem.php?problem=1097
My solution link: http://ideone.com/MF0yjB
How do I improve the complexity of my solution? Any help is really appreciated.
BIT problem from Light OJ (1097 - Lucky Number)
30.
suffix array related problem i need some critical input for light oj 1314 — Names for Babies
problem link is: http://lightoj.com/volume_showproblem.php?problem=1314
my code is: http://codepad.org/XsMUC5Lf
why wrong answer , i can't identify.
i need some critical input for light oj 1314 — Names for Babies problem link
is: http
31.
How to solve Light OJ 1058 — Parallelogram Counting ? I am new in geometry.I am trying to solve some basic problem about geometry.Hence i found a nice problem http://lightoj.com/volume_showproblem.php?problem=1058 . But I have no idea about this types of problem.
If anyone can help with some idea by how i solve this problem, i will be so much benefited. Please help me. Thanks in advance. :)
How to solve Light OJ 1058 — Parallelogram Counting ?
32.
Getting TLE in light oj problem : 1110 - An Easy LCS Topic : LCS
My code is getting TLE for this test case:
1
weuwmwxxeajlsalokh
dmnmklyoltvdpjzbkqe
How to solve this problem?
Question:
http://lightoj.com/volume_showproblem.php?problem=1110
My code:
https://ideone.com/WrNYdg
Getting TLE in light oj problem : 1110 - An Easy LCS
33.
Bit mask : Getting wa in light oj : 1021 Painful bases Topic : Bit mask.
Why getting wa in this test cases :
2
16 12
F853AD64B1EC7290
16 18
8192BEFA70CD3564
Correct Output :
Case 1: 5230697472000
Case 2: 3486618432000
My output :
Case 1: 2324797191360
Case 2: 1226335446000
Question :
http://lightoj.com/volume_showproblem.php?problem=1021
My code:
https://ideone.com/2XjGaV
Bit mask : Getting wa in light oj : 1021 Painful bases
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