计时器，随机数

RandomNum.java

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+
+package sort;
+
+
+public class RandomNum {
+    public int[] RandomGen(int n,int low, int high){
+        int[] r=new int[n];
+        int diff=high-low;
+        for(int i=0;i<n;i++){
+            r[i]=(int) (Math.random()*diff)+low;
+            
+            
+        }
+        return r;
+    }
+}

Stopwatch.java

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+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package sort;
+
+/**
+ *
+ * @author User
+ */
+public class Stopwatch {
+    private final long start;
+    
+    public Stopwatch(){
+        start=System.currentTimeMillis();
+    }
+    public double elapsedTime(){
+        long now=System.currentTimeMillis();
+        return (now-start)/1000.0;
+                
+    }
+    
+}