Algorithm (algorithms) version 4th practice 1.5.22

 packagecom.qiusongde;Importedu.princeton.cs.algs4.StdOut;Importedu.princeton.cs.algs4.StdStats; public classExercise1522 { public Static DoubleTIMETRIALFORQF (intTintNint[] edges) {Stopwatch Timer=NewStopwatch (); //repeat the experiment T times         for(intt = 0; T < t; t++) {edges[t]=ERDOSRENYI.COUNTBYQF (N); }                returnTimer.elapsedtime (); }         public Static DoubleTimetrialforweiqu (intTintNint[] edges) {Stopwatch Timer=NewStopwatch (); //repeat the experiment T times         for(intt = 0; T < t; t++) {edges[t]=Erdosrenyi.countbyweiqu (N); }                returnTimer.elapsedtime (); }         public Static DoubleMeanint[] edges) {        returnStdstats.mean (edges); }     public Static voidmain (string[] Args) {intT = Integer.parseint (args[0]); intedgesqf[] =New int[T]; intedgesqu[] =New int[T]; DoublePREVQF = TIMETRIALFORQF (T, 125, edgesqf); DoublePrevqu = Timetrialforweiqu (T, 125, edgesqu);  for(intN = 250;true; N + =N) {DoubleTIMEQF =TIMETRIALFORQF (T, N, edgesqf); Doubletimequ =timetrialforweiqu (T, N, edgesqu); DoubleMeanqfconnect =mean (edgesqf); DoubleMeanquconnect =mean (edgesqu); stdout.printf ("%6d%7.1f%7.1f%7.1f%7.1f\n", n, meanqfconnect, timeqf/prevqf, meanquconnect, timequ/prevqu); PREVQF=timeqf; Prevqu=timequ; }    }}

 packagecom.qiusongde;Importedu.princeton.cs.algs4.StdOut;Importedu.princeton.cs.algs4.StdRandom;Importedu.princeton.cs.algs4.StdStats;Importedu.princeton.cs.algs4.UF;Importedu.princeton.cs.algs4.WeightedQuickUnionUF; public classErdosrenyi { public Static intCountbyuf (intN) {intedges = 0; UF UF=NewUF (N);  while(uf.count () > 1) {            inti =Stdrandom.uniform (N); intj =Stdrandom.uniform (N);            Uf.union (i, j); Edges++; }                returnedges; }         public Static intCOUNTBYQF (intN) {intedges = 0; Ufquickfind uf=NewUfquickfind (N);  while(uf.count () > 1) {            inti =Stdrandom.uniform (N); intj =Stdrandom.uniform (N);            Uf.union (i, j); Edges++; }                returnedges; }         public Static intCountbyqu (intN) {intedges = 0; Ufquickunion uf=Newufquickunion (N);  while(uf.count () > 1) {            inti =Stdrandom.uniform (N); intj =Stdrandom.uniform (N);            Uf.union (i, j); Edges++; }                returnedges; }         public Static intCountbyweiqu (intN) {intedges = 0; Weightedquickunionuf uf=NewWeightedquickunionuf (N);  while(uf.count () > 1) {            inti =Stdrandom.uniform (N); intj =Stdrandom.uniform (N);            Uf.union (i, j); Edges++; }                returnedges; }         public Static voidmain (string[] Args) {intn = integer.parseint (args[0]);//Number of vertices            intTrials = Integer.parseint (args[1]);//Number of Trials            int[] edges =New int[trials]; //Repeat the experiment trials times             for(intt = 0; T < trials; t++) {edges[t]=Countbyuf (n); }            //report StatisticsSTDOUT.PRINTLN ("the" N ln n = "+ 0.5 * n *Math.log (n)); Stdout.println ("mean =" +Stdstats.mean (edges)); Stdout.println ("stddev =" +Stdstats.stddev (edges)); }}

 package   com.qiusongde;  public  class   Stopwatch { private  final  long   start;  public   Stopwatch () {start  = System.currenttimemillis ();  public  double   elapsedtime () { long  now = System        . Currenttimemillis ();     return  (now-start)/1000.0; }    }

Results:

      761.1     2.9   761.4     1.0 1698.6  2.8 1717.8 5.2 3739.0     3.8  3737.7     2.0  8184.8     3.7 8174.3  2.1     4000  17773.4     3.9 17799.1     2.2  8000 38312.6     4.1 38229.6     2.2

Algorithm (algorithms) version 4th practice 1.5.22