#працтицеЛинкДив { дисплаи: ноне !импортант; }Дат је скуп тачака ас и права као ак+би+ц = 0. Требамо пронаћи тачку на датој правој за коју је збир растојања од датог скупа тачака минималан.
Пример:

In above figure optimum location of point of x - y - 3 = 0 line is (2 -1) whose total distance with other points is 20.77 which is minimum obtainable total distance.Recommended Practice Оптимална локација тачке за минимизирање укупне удаљености Покушајте!
Ако узмемо једну тачку на датој правој на бесконачној удаљености онда ће укупни трошак удаљености бити бесконачан сада када ову тачку померимо на линији ка датим тачкама укупни трошак удаљености почиње да опада и након неког времена поново почиње да расте што је достигло бесконачност на другом бесконачном крају праве тако да крива трошкова удаљености изгледа као У-крива и морамо да пронађемо доњу вредност ове У-криве.
Како се У-крива не повећава монотоно или смањује, не можемо да користимо бинарну претрагу за проналажење најниже тачке овде ћемо користити тернарну претрагу за проналажење најниже тачке тернарно претраживање прескаче једну трећину простора за претрагу при свакој итерацији можете прочитати више о тернарној претрази овде .
Дакле, решење се наставља на следећи начин, почињемо са ниским и високим иницијализованим као неке најмање и највеће вредности, респективно, затим почињемо итерацију у свакој итерацији, израчунавамо две средине мид1 и мид2 које представљају 1/3. и 2/3. позицију у простору за претрагу, израчунавамо укупну удаљеност свих тачака са средином1 и мид2 и ажурирамо ниске или високе вредности упоређујући ове цене удаљености док ова ниска и висока итерација не постану приближно једнаке.
C++// C/C++ program to find optimum location and total cost #include using namespace std; #define sq(x) ((x) * (x)) #define EPS 1e-6 #define N 5 // structure defining a point struct point { int x y; point() {} point(int x int y) : x(x) y(y) { } }; // structure defining a line of ax + by + c = 0 form struct line { int a b c; line(int a int b int c) : a(a) b(b) c(c) { } }; // method to get distance of point (x y) from point p double dist(double x double y point p) { return sqrt(sq(x - p.x) + sq(y - p.y)); } /* Utility method to compute total distance all points when choose point on given line has x-coordinate value as X */ double compute(point p[] int n line l double X) { double res = 0; // calculating Y of chosen point by line equation double Y = -1 * (l.c + l.a * X) / l.b; for (int i = 0; i < n; i++) res += dist(X Y p[i]); return res; } // Utility method to find minimum total distance double findOptimumCostUtil(point p[] int n line l) { double low = -1e6; double high = 1e6; // loop until difference between low and high // become less than EPS while ((high - low) > EPS) { // mid1 and mid2 are representative x co-ordiantes // of search space double mid1 = low + (high - low) / 3; double mid2 = high - (high - low) / 3; // double dist1 = compute(p n l mid1); double dist2 = compute(p n l mid2); // if mid2 point gives more total distance // skip third part if (dist1 < dist2) high = mid2; // if mid1 point gives more total distance // skip first part else low = mid1; } // compute optimum distance cost by sending average // of low and high as X return compute(p n l (low + high) / 2); } // method to find optimum cost double findOptimumCost(int points[N][2] line l) { point p[N]; // converting 2D array input to point array for (int i = 0; i < N; i++) p[i] = point(points[i][0] points[i][1]); return findOptimumCostUtil(p N l); } // Driver code to test above method int main() { line l(1 -1 -3); int points[N][2] = { { -3 -2 } { -1 0 } { -1 2 } { 1 2 } { 3 4 } }; cout << findOptimumCost(points l) << endl; return 0; }
Java // A Java program to find optimum location // and total cost class GFG { static double sq(double x) { return ((x) * (x)); } static int EPS = (int)(1e-6) + 1; static int N = 5; // structure defining a point static class point { int x y; point() {} public point(int x int y) { this.x = x; this.y = y; } }; // structure defining a line of ax + by + c = 0 form static class line { int a b c; public line(int a int b int c) { this.a = a; this.b = b; this.c = c; } }; // method to get distance of point (x y) from point p static double dist(double x double y point p) { return Math.sqrt(sq(x - p.x) + sq(y - p.y)); } /* Utility method to compute total distance all points when choose point on given line has x-coordinate value as X */ static double compute(point p[] int n line l double X) { double res = 0; // calculating Y of chosen point by line equation double Y = -1 * (l.c + l.a * X) / l.b; for (int i = 0; i < n; i++) res += dist(X Y p[i]); return res; } // Utility method to find minimum total distance static double findOptimumCostUtil(point p[] int n line l) { double low = -1e6; double high = 1e6; // loop until difference between low and high // become less than EPS while ((high - low) > EPS) { // mid1 and mid2 are representative x // co-ordiantes of search space double mid1 = low + (high - low) / 3; double mid2 = high - (high - low) / 3; double dist1 = compute(p n l mid1); double dist2 = compute(p n l mid2); // if mid2 point gives more total distance // skip third part if (dist1 < dist2) high = mid2; // if mid1 point gives more total distance // skip first part else low = mid1; } // compute optimum distance cost by sending average // of low and high as X return compute(p n l (low + high) / 2); } // method to find optimum cost static double findOptimumCost(int points[][] line l) { point[] p = new point[N]; // converting 2D array input to point array for (int i = 0; i < N; i++) p[i] = new point(points[i][0] points[i][1]); return findOptimumCostUtil(p N l); } // Driver Code public static void main(String[] args) { line l = new line(1 -1 -3); int points[][] = { { -3 -2 } { -1 0 } { -1 2 } { 1 2 } { 3 4 } }; System.out.println(findOptimumCost(points l)); } } // This code is contributed by Rajput-Ji
Python3 # A Python3 program to find optimum location # and total cost import math class Optimum_distance: # Class defining a point class Point: def __init__(self x y): self.x = x self.y = y # Class defining a line of ax + by + c = 0 form class Line: def __init__(self a b c): self.a = a self.b = b self.c = c # Method to get distance of point # (x y) from point p def dist(self x y p): return math.sqrt((x - p.x) ** 2 + (y - p.y) ** 2) # Utility method to compute total distance # all points when choose point on given # line has x-coordinate value as X def compute(self p n l x): res = 0 y = -1 * (l.a*x + l.c) / l.b # Calculating Y of chosen point # by line equation for i in range(n): res += self.dist(x y p[i]) return res # Utility method to find minimum total distance def find_Optimum_cost_untill(self p n l): low = -1e6 high = 1e6 eps = 1e-6 + 1 # Loop until difference between low # and high become less than EPS while((high - low) > eps): # mid1 and mid2 are representative x # co-ordiantes of search space mid1 = low + (high - low) / 3 mid2 = high - (high - low) / 3 dist1 = self.compute(p n l mid1) dist2 = self.compute(p n l mid2) # If mid2 point gives more total # distance skip third part if (dist1 < dist2): high = mid2 # If mid1 point gives more total # distance skip first part else: low = mid1 # Compute optimum distance cost by # sending average of low and high as X return self.compute(p n l (low + high) / 2) # Method to find optimum cost def find_Optimum_cost(self p l): n = len(p) p_arr = [None] * n # Converting 2D array input to point array for i in range(n): p_obj = self.Point(p[i][0] p[i][1]) p_arr[i] = p_obj return self.find_Optimum_cost_untill(p_arr n l) # Driver Code if __name__ == '__main__': obj = Optimum_distance() l = obj.Line(1 -1 -3) p = [ [ -3 -2 ] [ -1 0 ] [ -1 2 ] [ 1 2 ] [ 3 4 ] ] print(obj.find_Optimum_cost(p l)) # This code is contributed by Sulu_mufi
C# // C# program to find optimum location // and total cost using System; class GFG { static double sq(double x) { return ((x) * (x)); } static int EPS = (int)(1e-6) + 1; static int N = 5; // structure defining a point public class point { public int x y; public point() {} public point(int x int y) { this.x = x; this.y = y; } }; // structure defining a line // of ax + by + c = 0 form public class line { public int a b c; public line(int a int b int c) { this.a = a; this.b = b; this.c = c; } }; // method to get distance of // point (x y) from point p static double dist(double x double y point p) { return Math.Sqrt(sq(x - p.x) + sq(y - p.y)); } /* Utility method to compute total distance of all points when choose point on given line has x-coordinate value as X */ static double compute(point[] p int n line l double X) { double res = 0; // calculating Y of chosen point // by line equation double Y = -1 * (l.c + l.a * X) / l.b; for (int i = 0; i < n; i++) res += dist(X Y p[i]); return res; } // Utility method to find minimum total distance static double findOptimumCostUtil(point[] p int n line l) { double low = -1e6; double high = 1e6; // loop until difference between // low and high become less than EPS while ((high - low) > EPS) { // mid1 and mid2 are representative // x co-ordiantes of search space double mid1 = low + (high - low) / 3; double mid2 = high - (high - low) / 3; double dist1 = compute(p n l mid1); double dist2 = compute(p n l mid2); // if mid2 point gives more total distance // skip third part if (dist1 < dist2) high = mid2; // if mid1 point gives more total distance // skip first part else low = mid1; } // compute optimum distance cost by // sending average of low and high as X return compute(p n l (low + high) / 2); } // method to find optimum cost static double findOptimumCost(int[ ] points line l) { point[] p = new point[N]; // converting 2D array input to point array for (int i = 0; i < N; i++) p[i] = new point(points[i 0] points[i 1]); return findOptimumCostUtil(p N l); } // Driver Code public static void Main(String[] args) { line l = new line(1 -1 -3); int[ ] points = { { -3 -2 } { -1 0 } { -1 2 } { 1 2 } { 3 4 } }; Console.WriteLine(findOptimumCost(points l)); } } // This code is contributed by 29AjayKumar
JavaScript <script> // A JavaScript program to find optimum location // and total cost function sq(x) { return x*x; } let EPS = (1e-6) + 1; let N = 5; // structure defining a point class point { constructor(xy) { this.x=x; this.y=y; } } // structure defining a line of ax + by + c = 0 form class line { constructor(abc) { this.a = a; this.b = b; this.c = c; } } // method to get distance of point (x y) from point p function dist(xyp) { return Math.sqrt(sq(x - p.x) + sq(y - p.y)); } /* Utility method to compute total distance all points when choose point on given line has x-coordinate value as X */ function compute(pnlX) { let res = 0; // calculating Y of chosen point by line equation let Y = -1 * (l.c + l.a * X) / l.b; for (let i = 0; i < n; i++) res += dist(X Y p[i]); return res; } // Utility method to find minimum total distance function findOptimumCostUtil(pnl) { let low = -1e6; let high = 1e6; // loop until difference between low and high // become less than EPS while ((high - low) > EPS) { // mid1 and mid2 are representative x // co-ordiantes of search space let mid1 = low + (high - low) / 3; let mid2 = high - (high - low) / 3; let dist1 = compute(p n l mid1); let dist2 = compute(p n l mid2); // if mid2 point gives more total distance // skip third part if (dist1 < dist2) high = mid2; // if mid1 point gives more total distance // skip first part else low = mid1; } // compute optimum distance cost by sending average // of low and high as X return compute(p n l (low + high) / 2); } // method to find optimum cost function findOptimumCost(pointsl) { let p = new Array(N); // converting 2D array input to point array for (let i = 0; i < N; i++) p[i] = new point(points[i][0] points[i][1]); return findOptimumCostUtil(p N l); } // Driver Code let l = new line(1 -1 -3); let points= [[ -3 -2 ] [ -1 0 ] [ -1 2 ] [ 1 2 ] [ 3 4 ]]; document.write(findOptimumCost(points l)); // This code is contributed by rag2127 </script>
Излаз
20.7652
Временска сложеност: О(н2)
Помоћни простор: О(н)