Infinite House of Pancakes [closed] - c++

Question

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
Improve this question
Here's a link to the problem in question: https://code.google.com/codejam/contest/6224486/dashboard#s=p1
Okay, so I got a bit hung up on this problem. Now that the quals are over, does anyone know why this wouldn't work? I've checked against about 50 different cases and haven't been able to find one that doesn't work. Here's my full code below.
Basically, looking for any cases where my algorithm could break.
//Includes
#include <iostream>
#include <fstream>
#include <list>
#include <algorithm>
#include <stdlib.h>
using namespace std;
//Functions
int solve(list<int>);
//Main
int main() {
int minutes = 0;
int numTestCases = 0;
int initNonEmpty = 0;
char tempChar;
int tempInt;
list<int> people;
//Import Data
//Get number of Test cases
ifstream infile;
infile.clear();
infile.open("B-small-attempt5.in");
//get NumTestCases
infile >> numTestCases;
int solution[numTestCases];
//Solve it
for(int i=0; i<numTestCases; i++){
//Reset vars
initNonEmpty=0;
infile >> initNonEmpty;
people.clear();
//Input data
for(int j=0; j<initNonEmpty; j++){
infile >> tempInt;
cout << tempInt;
people.push_back(tempInt);
}
cout << endl;
//Solve the set
people.sort();
people.reverse();
tempInt = solve(people);
cout << "Solve returns: " << tempInt << endl << endl;
solution[i] = tempInt;
}
//Output
ofstream outfile;
outfile.open("RealCase6.out");
for (int i=0; i < numTestCases; i++){
cout << "Case #" << i+1 << ": " << solution[i] << endl;
outfile << "Case #" << i+1 << ": " << solution[i] << endl;
}
}
int solve( list<int> data){
cout << "Starting Solve functions." << endl;
int tempMax;
int max =data.front();
int test=0;
cout << "Max: " << max << endl;
//Test if base case
if(max<=3){
cout << "Reached base case." << endl;
return max;
}
else if (max % 2 == 0 ){
cout << "Max is even" << endl;
tempMax = max/2;
data.pop_front();
data.push_back(tempMax);
data.push_back(tempMax);
data.sort();
data.reverse();
test=solve(data);
test=test+1;
cout << "test is:" << test << endl;
cout << "max is:" << max << endl;
if( test<=max){
return test;
} else {
return max;
}
}
else {
cout << "Max is odd" << endl;
tempMax = max/2;
data.pop_front();
data.push_back(tempMax);
data.push_back(tempMax+1);
data.sort();
data.reverse();
test=solve(data);
test=test+1;
cout << "test is:" << test << endl;
cout << "max is:" << max << endl;
if(test<=max){
return test;
} else {
return max;
}
}
}
And here's my input/output for 6 different cases.
https://www.dropbox.com/sh/55wq52lzuygd82s/AABYxJJ7zaeoMhgCmymJcwnAa?dl=0
I'll remove this if this is too early to start asking about the problems. Sorry about eh formatting, but I was trying to get this done quickly.
Edit1: Added Link to problem.
Edit2: Someone else found the error. I only thought to divide things into groups of 2, which gives a case of one person with 9 pancakes, where dividing it into a group of 6 and 3 and then 3 3 3 works best.

Answer 1

This breaks in cases where it's more efficient to divide into non-equivalent stacks. For example, the case
1
9
where one person has 9 pancakes. Dividing as evenly as possible into groups of 2 gives the solution:
min 1: 9
min 2: 5 4
min 3: 4 3
min 4: 3 2
min 5: 2 1
min 6: 1 0
min 7: 0 0
where as dividing unevenly gives the solution
min 1: 9
min 2: 3 6
min 3: 3 3 3
min 4: 2 2 2
min 5: 1 1 1
min 6: 0 0 0
which is more efficient.