Coursera algorithms week2 Basic sort interview Questions:1 intersection of the sets

Original title:

Given Arrays a[] and b[], each containing n distinct 2D points in the plane, design a subquadratic algorithm to count The number of points that is contained both in array a[] and array b[].

The goal of the topic is to calculate the number of duplicate point, very simple, the code is as follows

1 ImportJava.awt.Point;2 Importjava.util.Arrays;3 ImportJava.util.HashSet;4 ImportJava.util.Set;5 6 ImportEdu.princeton.cs.algs4.StdRandom;7 8  Public classplanepoints {9     Privateset<point> s =NewHashset<point>();Ten     Private intSamepointsnum; OnePlanepoints (intn,point[] Inputa, point[] inputb) { A              for(inti=0;i<n;i++){ - S.add (Inputa[i]); - S.add (Inputb[i]); the         } -Samepointsnum = 2*n-s.size (); -     } -      +      Public intSamepointsnum () { -         returnSamepointsnum; +     } A      at      Public Static voidMain (string[] args) { -         intn = 10; -Point[] A =NewPoint[n]; -Point[] B =NewPoint[n]; - System.out.println (a.length); -          for(inti=0;i<n;i++){ inA[i] =NewPoint (); - a[i].setlocation (Stdrandom.uniform (n), Stdrandom.uniform (n)); toB[i] =NewPoint (); + b[i].setlocation (Stdrandom.uniform (n), Stdrandom.uniform (n)); -         } the System.out.println (Arrays.tostring (a)); * System.out.println (arrays.tostring (b)); $Planepoints pp =Newplanepoints (n,a,b);Panax Notoginseng System.out.println (pp.samepointsnum); -     } the}

Coursera algorithms week2 Basic sort interview Questions:1 intersection of the sets