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I think I used a simpler method for C, this is the observation:

Let M be the maximum of {b, d, s}; then the other 2 would be in the best case M — 1. So if b is the maximum, then (d >= b — 1 and s >= b — 1) always holds true.

This is the code: http://codeforces.net/contest/732/submission/21550209

"Теперь просуммируем изменённые значения b, d, s в переменную sum, возьмём среди них максимум (переменная mx)"

1. Как мы меняем значения b, d, s?
2. Почему вообще мы их трогаем?
3. Почему мы их суммируем?
4. Откуда берётся правильность выражения mx  -  3·sum?

Какая картина стоит за этими алгебраическими операциями?

В моём представлении всё выглядит так:
int mx = max(b, max(d, s));
int totalMeals = 3 * mx;
int missedMealsUpperBoundEstimate = totalMeals - b - d - s;

И нам нужно уменьшать missedMealsUpperBoundEstimate, а НЕ b, d, s. Где я туплю? =)

can someone explain last line for f. with example? why orient (v,to) to (to,v)?

Hi, I'm not understanding why my submission is getting TLE for Div2 F. can anyone please check it? Here's my submission, 21830666 I have implemented it exactly as given in the tutorial.

In Problem B, test-10:

Input
5 2
0 0 0 1 0
Output
4
0 2 1 1 1 
Answer
3
0 2 0 2 0
Checker Log
wrong answer Jury answer is better.

Obviously my answer is better?

Div2D Exams

Consider the following test case

10 3
0 3 0 1 0 0 0 0 2 0
1 1 4

The following AC submission gives the answer as 9. I would like to know how is the answer 9 correct. Since subject 3 requires 4 days of preparation, which clearly isn't possible, shouldn't the answer be -1 ?

#include<bits/stdc++.h>  
using namespace std;  
int main()  
{  
int n,m;  
cin>>n>>m;  
int arr[n+1];  
for(int i=1;i<=n;i++)cin>>arr[i];  
int sum=m,x;  
for(int i=0;i<m;i++){cin>>x; sum+=x;}  
  
for(int i=sum;i<=n;i++)if(arr[i]){cout<<i; return 0;}  
cout<<-1;  
}

can someone provide an explanation on why is the mentioned strategy of orienting edges in problem F optimal? i.e. why does it allow us to traverse from any vertex to any other vertex in an 'edge' connected component?

Test cases for D are very trivial. All of them pass through wrong solution also.

Can anyone provide proof of correctness for problem F ? I am not sure whether the solution in tutorial is correct

Can someone please explain the editorial of Problem F? I can't get why the answer is the largest component!

Problem D please someone Add this Test Case if possible

17 3
0 0 1 0 2 0 3 0 0 0 0 3 0 0 0 0 1
6 1 1

My Code Output
12

Actual Output
17

Still it got Accepted

the test cases of problem D are weak.my solution is wrong but got ac. for the test case
16 3
0 0 1 0 2 0 0 3 0 0 0 0 0 0 0 1
2 4 7
ans should be -1 but mine gives 16

Actually we don't need to find bridges in problem F. For every edge $$$(u, v)$$$ in our DFS path, just orient it from $$$v$$$ to $$$u$$$. Refer to my submission: 117700144.

Can someone please explain D