Subtraction with #define

[dleanjeanz]

Problem: http://www.codechef.com/problems/TLG
I have written a solution to solve the problem in the link above. I have #define-d as in the codes below to get the bigger and the smaller numbers. I tested it with the sample input in the link but it did not output as my expectation. The sample output is: 1 58, but mine was: 1 140. So I tried to debug it, here what I got:

As you can see, the second line of the input is: 140 82
So si == 140 and ti == 82
max(si, ti) == si == 140
min(si, ti) == ti == 82
but max(si, ti) - min(si, ti) == 140 //max minus min
Why?

  #include <iostream>
#define max(a,b) a>b?a:b
#define min(a,b) a<b?a:b
#define lead(a,b) a>b?1:2

using namespace std;

int main()
{
   unsigned int n, si, ti, W, L = 0;
   cin >> n;
   for (int i = 0; i < n; i++) {
       cin >> si >> ti;
       int l = max(si,ti) - min(si,ti); \\problem here
       if (l > L) {
           W = lead(si, ti);
           L = l;
       }
   }
   
   cout << W << ' ' << L;
   
   return 0;
}

I used

int max(int a, int b) return a>b?a:b;

int min(int a, int b) return a<b?a:b;

instead of #define-ing and it worked but still need to know why? (The question up there)

[mutexe]

is there any reason you are trying to use macro's? They are evil (mostly).

[dleanjeanz]

It just popped up in my head when I was coding.

[mutexe]

well i think this is what your line 14 evaluates to after preprocessing (i think):

si>ti?si:ti-si<ti?si:ti

Not nice. I'm not even sure what the minus is actually doing in this case.

edit: have a read of this:
http://stackoverflow.com/questions/14041453/why-are-preprocessor-macros-evil-and-what-are-the-alternatives

[dleanjeanz]

So

#include <iostream>

using namespace std;

int max(int a, int b) {
	if (a>b) return a;
	return b;
}

int min(int a, int b) {
	if (a<b) return a;
	return b;
}

int lead(int a, int b) {
	if (a>b) return 1;
	return 2;
}

int main()
{
   int n, si, ti, W, L = 0;
   cin >> n;
   for (int i = 0; i < n; i++) {
       cin >> si >> ti;
       int l = max(si,ti) - min(si,ti);
       if (l > L) {
           W = lead(si, ti);
           L = l;
       }
   }
   
   cout << W << ' ' << L << '\n';
   
   return 0;
}

Submitted
Got wrong answer
Sucks

[mutexe]

if i type

1
140 40

my output is

1 100

That looks right to me, so check your looping.
Are you meant to be summing the results for each player to determine the winner? The example has this:

140 82
89 134
90 110
112 106
88 90

but says player one is the winner? So i guess it's just looking at the highest value regardless of the number of 'games'?


edit: okay, i've read it properly now sorry.

You want to store the results and the difference in a vector or something.
then when you've got them all search that vector for the highest value.

[mutexe]

OP: bit of a rush job and needs tidying, but...

#include <iostream>
#include <tuple>
#include <vector>



int getMax(int a, int b) {
	return a>b?a:b;
}

int getMin(int a, int b) {
	return a<b?a:b;
}

std::tuple<int,int,int> GetElementWithBiggestDifference(std::vector<std::tuple<int,int,int>> scores)
{
	std::tuple<int,int,int> maxValue(std::make_tuple(-1, -1, -1));
	std::vector<std::tuple<int,int,int>>::iterator it;

	for(it = scores.begin(); it!= scores.end();it++)
	{
		std::tuple<int,int,int> rtn = *it;
		int difference = std::get<2>(rtn);

		if(abs(difference) > abs(std::get<2>(maxValue)))
		{
			maxValue = *it;
		}
	}

	return maxValue;
}



int main()
{
	std::vector<std::tuple<int,int,int>> scores;

	int n, si, ti;
	std::cin >> n;

	for (int i = 0; i < n; i++) {		
		
		std::cin >> si >> ti;
		scores.push_back(std::make_tuple(si, ti, si-ti)); 		
	}


	std::tuple<int,int,int> elementOfInterest = GetElementWithBiggestDifference(scores);


	int playerWon = (std::get<2>(elementOfInterest) > 0) ? 1 : 2;
	int playerOneScore = std::get<0>(elementOfInterest);
	int playerTwoScore = std::get<1>(elementOfInterest);

	// calc difference & print to screen.

	return 0;
}

[dleanjeanz]

Reading it and seeing what tuple is.
http://www.cplusplus.com/reference/tuple/tuple/

Update:
It's kinda complex. I have to leave now. I'll come back tomorrow. See ya.

[mutexe]

it's simpler than yours :)
For example, why are you even calculating min and max of the scores?
You don't need to use tuples at all, you could use a normal array.

[dleanjeanz]

Yesterday, I realized that I had read the problem without regard. The scores of a round are sums of all previous scores (in all previous rounds). So:

#include <iostream>
#include <cmath>

using namespace std;

int lead(int a, int b) {
	if (a>b) return 1;
	return 2;
}

int main()
{
   int n, si, ti, Si = 0, Ti = 0, W, L = 0;
   cin >> n;
   for (int i = 0; i < n; i++) {
       cin >> si >> ti;
       Si = si += Si; Ti = ti += Ti;
       int l = abs(si-ti);
       if (l > L) {
           W = lead(si, ti);
           L = l;
       }
   }
   
   cout << W << ' ' << L << '\n';
   
   return 0;
}

solve the problem. Thanks for your help.