Added findClosestPair()

Author: osemrt

Diff for: closest_pair_problem/bruteForce.c

@@ -0,0 +1,22 @@
+#include "header_files/declarations.h"
+
+PairedPoints* bruteForce(Point* points, int left, int right) {
+
+	int minDistance = INT_MAX;
+	double calculatedDistance;
+	PairedPoints* closestPaired = (PairedPoints*)malloc(sizeof(PairedPoints));
+
+	for (int i = left; i <= right; i++) {
+		for (int j = i + 1; j <= right; j++) {
+			calculatedDistance = calculateDistance(points[i], points[j]);
+			if (calculatedDistance < minDistance) {
+				closestPaired->p1 = points[i];
+				closestPaired->p2 = points[j];
+				closestPaired->distance = calculatedDistance;
+			}
+		}
+	}
+
+	return closestPaired;
+
+}

Diff for: closest_pair_problem/calculateDistance.c

@@ -0,0 +1,7 @@
+#include "header_files/declarations.h"
+
+int calculateDistance(Point p1, Point p2) {
+	int diffX = p1.x - p2.x;
+	int diffY = p1.y - p2.y;
+	return sqrt(pow(diffX, 2) + pow(diffY, 2));
+}

Diff for: closest_pair_problem/findClosestPair.c

@@ -0,0 +1,36 @@
+#include "header_files/declarations.h"
+
+PairedPoints findClosestPair(Point* points, int left, int right) {
+
+	int numOfPoints = (right - left) + 1;
+	if (numOfPoints <= 3)
+		return *bruteForce(points, left, right);
+
+	int mid = (left + right) / 2;
+
+	PairedPoints minPPL = findClosestPair(points, left, mid);
+	PairedPoints minPPR = findClosestPair(points, mid + 1, right);
+
+	PairedPoints minPP;
+	if (minPPL.distance < minPPR.distance)
+		minPP = minPPL;
+	else
+		minPP = minPPR;
+
+	Point split[MAX];
+	int j = 0;
+	for (int i = left; i <= right; i++) {
+		if (abs(points[i].x - points[mid].x) < minPP.distance) {
+			split[j] = points[i];
+			j++;
+		}
+	}
+
+	PairedPoints PPM = lookNearOfMid(split, j, minPP.distance);
+
+	if (PPM.distance != INT_MIN)
+		return PPM;
+	else
+		return minPP;
+
+}

Diff for: closest_pair_problem/header_files/common.h

@@ -2,13 +2,16 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <math.h>
 
 #define TRUE 1
 #define FALSE 0
 
 #define x_axis 1
 #define y_axis 0
 
+#define MAX 2000 //for split array
+
 
 typedef struct {
 	int x;
@@ -18,5 +21,6 @@ typedef struct {
 typedef struct {
 	Point p1;
 	Point p2;
+	double distance;
 }PairedPoints;
 

Diff for: closest_pair_problem/header_files/declarations.h

@@ -7,4 +7,9 @@ int eliminateSamePoints(Point* arr, int N);
 void printPoints(Point* points, int N);
 void quickSort(Point arr[], int first, int last, int axis);
 int partition(Point arr[], int first, int last, int axis);
-int swap(int arr[], int index1, int index2);
+int swap_x_axis(Point arr[], int index1, int index2);
+int swap_y_axis(Point arr[], int index1, int index2);
+PairedPoints* bruteForce(Point* points, int left, int right);
+int calculateDistance(Point p1, Point p2);
+PairedPoints lookNearOfMid(Point split[], int size, int minDistance);
+PairedPoints findClosestPair(Point* points, int left, int right);

Diff for: closest_pair_problem/lookNearOfMid.c

@@ -0,0 +1,24 @@
+#include "header_files/declarations.h"
+
+PairedPoints lookNearOfMid(Point split[], int size, int minDistance) {
+
+	quickSort(split, 0, size - 1, y_axis);
+	printPoints(split, size);
+	PairedPoints closestPairedPoints;
+	closestPairedPoints.distance = INT_MIN; //to control
+
+	for (int i = 0; i < size; i++) {
+		for (int j = i + 1; j < size; j++) {
+			if (abs(split[i].y - split[j].y) < minDistance) {
+				closestPairedPoints.p1 = split[i];
+				closestPairedPoints.p2 = split[j];
+				closestPairedPoints.distance = calculateDistance(split[i], split[j]);
+			}
+			
+
+		}
+	}
+
+	return closestPairedPoints;
+
+}