各排序算法及其比较

Posted 2020-09-21 Wujunde

heap:

public class heap {
public static void sort(int[]a){
int b[] = copy(a);
int N = b.length-1;
for(int k = N/2;k > 0;k--){
sink(b,k,N);
}
while(N > 1){
exch(b,1,N--);
sink(b,1,N);
}
//for(int i = 1;i < b.length; i++){
//System.out.println(b[i] + " ");

// }


}

public static int[] copy(int[] a){
int n = a.length;
int[] copy = new int[a.length + 1];
for(int i = n;i>0;i--){
copy[i] = a[i-1];
}
copy[0] = -1;
return copy;
}

private static void sink(int[]a,int k,int N){
while (2*k <= N){
int j = 2*k;
if(j < N && a[j] < a[j+1]){j++;}
if(a[j] > a[k]){
exch(a,k,j);}
else{break;}
k = j;
}
}
public static void exch(int[] a,int i,int j)
{ int t = a[i]; a[i] = a[j] ; a[j] = t;}
}

------------------------------------------------------------------------------------------------

Insertion:

public static void sort(int[] a) {
int n = a.length;
int[] b = copy(a);
for (int i = 0; i < n; i++) {
for (int j = i; j > 0 && less(b[j], b[j-1]); j--) {
exch(b, j, j-1);
}
//assert isSorted(a, 0, i);
}
// for(int i = 0;i < a.length; i++)
//System.out.println(b[i] + " ");
//assert isSorted(a);
}
private static boolean less(int v,int w)
{ return v-w < 0; }

private static void exch(int[] a,int i,int j)
{ int t = a[i]; a[i] = a[j] ; a[j] = t;}

public static boolean isSorted(int[] a)
{
for(int i = 1; i < a.length; i++)
if(less(a[i],a[i-1])) return false;
return true;
}



private static int[] copy(int[] a){
int n = a.length;
int[] copy = new int[a.length];
for(int i = n;i>0;i--){
copy[i-1] = a[i-1];
}
return copy;
}
/* public static void main(String[] args)
{
String[] a = args;
sort(a);
assert isSorted(a);
show(a);

}*/

}

-------------------------------------------------------------------------------------------------------

quicksort:

public static void sort(int[] a) {
int n = a.length;
int[] b = merge.copy(a);
qs(b,0,n-1);
//for(int i = 0;i < b.length; i++){
//System.out.println(b[i] + " ");

// }
//assert isSorted(a);
}
//}


public static void qs(int[] a,int lo,int hi){
int mid = 0;
if(lo < hi){
mid = partition(a,lo,hi);
qs(a,lo,mid-1);
qs(a,mid+1,hi);
}
}
public static int partition(int[] a,int lo,int hi){
int key = a[hi];
int i = lo -1;
for(int j = lo;j <= hi -1;j++){
if(a[j] < key){
i = i+1;
heap.exch(a,i,j);
}
}
heap.exch(a,i+1,hi);
return i+1;

}

}

--------------------------------------------------------------------------------------------------

 binarytree:

public class binarytree {
///private Node root = null;
private static class Node{
private int val;
private Node left,right;
private int N; //the number of the all nodes of its child nodes and itself
//private int num;//the number
public Node(int val,int N){
this.val = val; this.N = N;
}

}

public static void sort(int[] a) {
int n = a.length;
Node root = null;
for(int i = n-1;i >= 0;i-- ){
root = put(root,a[i]);
}
int[] b = new int[n];
for(int i = n-1;i >= 0;i-- ){
Node x = select(root,i);
b[i] = x.val;
}
// for(int i = 0;i < b.length; i++){
//System.out.println(b[i] + " ");

// }

}

private static Node put(Node x,int val){
if(x == null) return new Node(val,1);
if(val < x.val) x.left = put(x.left,val);
else if(val > x.val) x.right = put(x.right,val);
else x.val = val;
x.N = size(x.left) + size(x.right) + 1;
return x;
}
private static int size(Node x){
if(x == null){return 0;}
else return x.N;
}



private static Node select(Node x,int k){
if(x == null) return null;
int t = size(x.left);
if (t>k) return select(x.left,k);
else if(t<k) return select (x.right,k-t-1);
else return x;
}



}

-------------------------------------------------------------------------------------------------------------

merge:

public static void sort(int[] a) {
int n = a.length;
int[] b = copy(a);
for (int sz = 1; sz < n; sz = 2*sz) {
for (int lo = 0; lo < n-sz; lo = lo +2*sz) {
merge1(b,lo,lo + sz - 1,Math.min(lo +2*sz-1, n-1));
}



//assert isSorted(a, 0, i);
}
// for(int i = 0;i < b.length; i++){
//System.out.println(b[i] + " ");

// }
//assert isSorted(a);
}

public static void merge1(int[] a, int lo, int mid, int high){
int[] aux = new int[a.length];
int i = lo,j = mid +1;
for(int k = lo; k <= high ; k++)
{
aux[k] = a[k];
}
for(int k = lo; k <= high ; k++)
{
if(i >= mid + 1)
{
a[k] = aux[j++];
}
else if(j > high)
{
a[k] = aux[i++];
}

else if(aux[i] < aux[j])
{
a[k] = aux[i++];
}
else
{
a[k] = aux[j++];
}
}

}

public static int[] copy(int[] a){
int n = a.length;
int[] copy = new int[a.length ];
for(int i = n-1;i>=0;i--){
copy[i] = a[i];
}
return copy;
}


/* public static void main(String[] args)
{
//String[] a = null;
sort(args);
//assert isSorted(a);
//show(a);
}*/
}

--------------------------------------------------------------------------------------------------------------------

comparison:

public class mysort {


public static void main(String[] args){
int number = 50000;
int[] array = new int[number] ;
boolean flag = true;
Random random = new Random();
FileWriter writer = null;

try {

writer = new FileWriter("D:\\input.txt", false);
for(int i = number;i > 0 ;i--){
int r = random.nextInt(100000);
flag = true;
for(int k = number-i -1;k >=0;k--){
if(r == array[k]){ flag = false; i++;}
}
if(flag == true){ array[number-i] = r;
String s = Integer.toString(r);
//System.out.println(s);
writer.write(s + " "); }
//if(i % 5 == 0){
//writer.write("\n");
//}
}
} catch (IOException e) {
System.out.println("no1");
} finally {
try {
if(writer != null){
writer.close();
}
} catch (IOException e) {
System.out.println("no2");
}
}
long startTime = System.currentTimeMillis();

Insertion.sort(array);

long endTime = System.currentTimeMillis();

System.out.println("Insertion " + (endTime - startTime)+ "ms");


startTime = System.currentTimeMillis();

heap.sort(array);

endTime = System.currentTimeMillis();

System.out.println("heap " + (endTime - startTime) + "ms");

startTime = System.currentTimeMillis();

merge.sort(array);

endTime = System.currentTimeMillis();

System.out.println("merge " + (endTime - startTime) + "ms");


startTime = System.currentTimeMillis();

quicksort.sort(array);

endTime = System.currentTimeMillis();

System.out.println("quicksort " + (endTime - startTime) + "ms");


startTime = System.currentTimeMillis();

binarytree.sort(array);

endTime = System.currentTimeMillis();

System.out.println("binarytree " + (endTime - startTime) + "ms");

}
}

--------------------------------------------------------------------------------------------------------------------------------

report:

100 int type number from 0 to 500
Insertion 2ms
heap 1ms
merge 1ms
quicksort 1ms
binarytree 3ms

1000 int type number from 0 to 5000
Insertion 10ms
heap 1.5ms
merge 2.5ms
quicksort 2ms
binarytree 4ms

10000 int type number from 0 to 50000
Insertion 73ms
heap 4ms
merge 103ms
quicksort 4ms
binarytree 12ms

50000 int type number from 0 to 100000
Insertion 1769ms
heap 15ms
merge 1233ms
quicksort 12ms //not stable(1x-8x)
binarytree 33ms