origin.h File Reference

#include <iostream>
#include <bits/stdc++.h>

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Macros
#define	ull   unsigned long long
#define	pb   push_back
#define	mp   make_pair
#define	COLLINEAR   1
#define	CLOCKWISE   2
#define	ANTICLOCKWISE   3

Functions
double	calcEuclidDistance (pair< double, double > fpoint, pair< double, double > spoint)
	Euclidean Distance. More...
int	orientation (pair< double, double > a, pair< double, double > b, pair< double, double > c)
	Orientation. More...
bool	orderedSort (pair< double, double > &f, pair< double, double > &s)
	Comparator Function. More...
bool	orderedYSort (pair< double, double > &f, pair< double, double > &s)
	Comparator Function Sort by y coordinate. More...
bool	orderByPolar (pair< double, double > &p1, pair< double, double > &p2)
	Function to order with respect to polar Coordinates. More...
void	printVectorData (int len, vector< pair< double, double > > v, string s)
	Print Function. More...
vector< pair< double, double > >	getData (char *filename)
	Extract Data from Input File. More...

Variables
vector< int >	indices
pair< double,double >	P0
	a double value which stores the centre about which polar ordering is to be done More...

Macro Definition Documentation

#define ANTICLOCKWISE   3

Macro defined for identifying 3 points that rotate anticlockwise

#define CLOCKWISE   2

Macro defined for identifying 3 points that rotate clockwise

#define COLLINEAR   1

Macro defined for identifying 3 collinear points

#define mp   make_pair

Macro for making my typing life easier

#define pb   push_back

Macro for making my typing life easier

#define ull   unsigned long long

Macro for making my typing life easier

Function Documentation

double calcEuclidDistance	(	pair< double, double >	fpoint,
		pair< double, double >	spoint
	)

Euclidean Distance.

This function is used to calculate the distance between two points which is .

                                                                                    {
    double dist;
    dist = sqrt(pow((fpoint.first-spoint.first),2.0) + pow((fpoint.second-spoint.second),2.0));
    return dist;
}

vector<pair<double, double> > getData

(

char *

filename

)

Extract Data from Input File.

It extracts Data From a file and stores it in a vector for further calculation. Forms the base for getting Data.

                                                      {
    vector<pair<double, double> > input;
    double a,b;
    ifstream in_file;
    in_file.open(filename);
    while (in_file.is_open()) {
        int n;
        in_file >> n;
        while(in_file >> a >> b) {
            input.pb(mp(a,b));
        }
        in_file.close();
    }
    return input;
}

bool orderByPolar	(	pair< double, double > &	p1,
		pair< double, double > &	p2
	)

Function to order with respect to polar Coordinates.

function used by this algorithm to sort an array of points with respect to the first point in the vector.

                                                                   {
    int oValue  = orientation(P0,p2,p1);
    cout << "comparing " << "(" << P0.first << ", " << P0.second <<")" <<  " "
         << "(" << p1.first << ", " << p1.second <<")" << " "
         << "(" << p2.first << ", " << p2.second <<")" <<endl;
    cout << " The orientation value is " << oValue << endl;
    if(oValue == 1) {
        cout << "Result :" << (calcEuclidDistance(P0,p2) >= calcEuclidDistance(P0,p1)) <<endl;
        return (calcEuclidDistance(P0,p2) < calcEuclidDistance(P0,p1));
    }
    return (oValue != 3);
}

bool orderedSort	(	pair< double, double > &	f,
		pair< double, double > &	s
	)

Comparator Function.

This function basically compares a pair of elements by the values of their x-coordinate and if x-xoordinate is equal then it checks for equality of y-coordinate

                                                                 {
    //cout << "Comparing (" << f.first << ", " << f.second <<")" << " (" << s.first << ", " << s.second <<")" << endl;
    if(f.first < s.first) {
        return true;
    }
    if (f.first > s.first) {
        return false;
    }
    return f.second<s.second;
}

bool orderedYSort	(	pair< double, double > &	f,
		pair< double, double > &	s
	)

Comparator Function Sort by y coordinate.

This function basically compares a pair of elements by the values of their y-coordinate and if x-xoordinate is equal then it checks for equality of x-coordinate

                                                                  {
    if(f.second < s.second) {
        return true;
    }
    if (f.second > s.second) {
        return false;
    }
    return f.first<s.first;
}

int orientation	(	pair< double, double >	a,
		pair< double, double >	b,
		pair< double, double >	c
	)

Orientation.

This function is used to calculate orientation of 3 points namely clockwise, anticlockwise and collinear. The idea here is to to get the difference between slopes of 2 lines by assuming a particular direction as a result the result obtained determines the direction of turn of the three points.

                                                                                        {
    double m1, m2, dif;
    dif = (b.second - a.second)*(c.first-b.first) - (b.first-a.first)* (c.second - b.second);
    cout << "Difference in Slopes " << dif<<endl;
    if(dif == 0) {
        cout << "COLLINEAR\n";
        return COLLINEAR;
    } else if (dif > 0 ) {
        cout << "CLOCKWISE\n";
        return CLOCKWISE;
    } else {
        cout << "ANTICLOCKWISE\n";
        return ANTICLOCKWISE;
    }
}

void printVectorData	(	int	len,
		vector< pair< double, double > >	v,
		string	s
	)

Print Function.

Prints content of the vector. Used for output formatting

                                                                         {
    int i;
    cout << s << v.size() << endl;
    for(i=0;i<len;i++)
        cout << v[i].first <<" " << v[i].second <<endl;
}

Variable Documentation

vector<int> indices

pair<double ,double > P0

a double value which stores the centre about which polar ordering is to be done