2016 Update

Task/Closest-pair-problem/Pascal/closest-pair-problem.pascal

@@ -0,0 +1,67 @@
+program closestPoints;
+{$IFDEF FPC}
+   {$MODE Delphi}
+{$ENDIF}
+const
+  PointCnt = 10000;//31623;
+type
+  TdblPoint = Record
+               ptX,
+               ptY : double;
+              end;
+  tPtLst =  array of TdblPoint;
+
+  tMinDIstIdx  = record
+                   md1,
+                   md2 : NativeInt;
+                 end;
+
+function ClosPointBruteForce(var  ptl :tPtLst):tMinDIstIdx;
+Var
+  i,j,k : NativeInt;
+  mindst2,dst2: double; //square of distance, no need to sqrt
+  p0,p1 : ^TdblPoint;   //using pointer, since calc of ptl[?] takes much time
+Begin
+  i := Low(ptl);
+  j := High(ptl);
+  result.md1 := i;result.md2 := j;
+  mindst2 := sqr(ptl[i].ptX-ptl[j].ptX)+sqr(ptl[i].ptY-ptl[j].ptY);
+  repeat
+    p0 := @ptl[i];
+    p1 := p0; inc(p1);
+    For k := i+1 to j do
+    Begin
+      dst2:= sqr(p0^.ptX-p1^.ptX)+sqr(p0^.ptY-p1^.ptY);
+      IF mindst2 > dst2  then
+      Begin
+        mindst2 :=  dst2;
+        result.md1 := i;
+        result.md2 := k;
+      end;
+      inc(p1);
+    end;
+    inc(i);
+  until i = j;
+end;
+
+var
+  PointLst :tPtLst;
+  cloPt : tMinDIstIdx;
+  i : NativeInt;
+Begin
+  randomize;
+  setlength(PointLst,PointCnt);
+  For i := 0 to PointCnt-1 do
+    with PointLst[i] do
+    Begin
+      ptX := random;
+      ptY := random;
+    end;
+  cloPt:=  ClosPointBruteForce(PointLst) ;
+  i := cloPt.md1;
+  Writeln('P[',i:4,']= x: ',PointLst[i].ptX:0:8,
+                     ' y: ',PointLst[i].ptY:0:8);
+  i := cloPt.md2;
+  Writeln('P[',i:4,']= x: ',PointLst[i].ptX:0:8,
+                     ' y: ',PointLst[i].ptY:0:8);
+end.