first commit

QuickSort.java

@@ -0,0 +1,39 @@
+package sort;
+
+
+public class QuickSort {
+    
+    private static void exch(int[] a,int i,int j){
+        int t=a[i];
+        a[i]=a[j];
+        a[j]=t;
+}
+    
+    private static int partition(int[] a,int lo,int hi){
+        int i=lo,j=hi+1;
+        int v=a[lo];
+        while(true){
+            while(a[++i]<v)
+                if(i==hi)
+                    break;
+            while(a[--j]>v)
+                if(j==lo)
+                    break;
+            if(i>=j)
+                break;
+            exch(a,i,j);
+        }
+        exch(a,lo,j);
+        return j;
+    }
+    private static void sort(int[] a, int lo,int hi){
+        if(hi<=lo)
+            return;
+        int j=partition(a,lo,hi);
+        sort(a,lo,j-1);
+        sort(a,j+1,hi);
+    }
+    public void sort(int[] a){
+        sort(a,0,a.length-1);
+    }
+}