排序算法復(fù)習(xí)（Java實(shí)現(xiàn)）： 插入,，冒泡，選擇,，Shell,快速排序 收藏為了便于管理，先引入個基礎(chǔ)類： package algorithms;
/** * @author yovn * */ public abstract class Sorter<E extends Comparable<E>> { public abstract void sort(E[] array,int from ,int len); public final void sort(E[] array) { sort(array,0,array.length); } protected final void swap(E[] array,int from ,int to) { E tmp=array[from]; array[from]=array[to]; array[to]=tmp; } } 一 插入排序 package algorithms;
/** * @author yovn */ public class InsertSorter<E extends Comparable<E>> extends Sorter<E> { /* (non-Javadoc) * @see algorithms.Sorter#sort(E[], int, int) */ public void sort(E[] array, int from, int len) { E tmp=null; for(int i=from+1;i<from+len;i++) { tmp=array[i]; int j=i; for(;j>from;j--) { if(tmp.compareTo(array[j-1])<0) { array[j]=array[j-1]; } else break; } array[j]=tmp; } } }
package algorithms;
/** * @author yovn * */ public class BubbleSorter<E extends Comparable<E>> extends Sorter<E> { private static boolean DWON=true; public final void bubble_down(E[] array, int from, int len) { for(int i=from;i<from+len;i++) { for(int j=from+len-1;j>i;j--) { if(array[j].compareTo(array[j-1])<0) { swap(array,j-1,j); } } } } public final void bubble_up(E[] array, int from, int len) { for(int i=from+len-1;i>=from;i--) { for(int j=from;j<i;j++) { if(array[j].compareTo(array[j+1])>0) { swap(array,j,j+1); } } } } @Override public void sort(E[] array, int from, int len) { if(DWON) { bubble_down(array,from,len); } else { bubble_up(array,from,len); } } }
package algorithms;
/** * @author yovn * */ public class SelectSorter<E extends Comparable<E>> extends Sorter<E> { /* (non-Javadoc) * @see algorithms.Sorter#sort(E[], int, int) */ @Override public void sort(E[] array, int from, int len) { for(int i=0;i<len;i++) { int smallest=i; int j=i+from; for(;j<from+len;j++) { if(array[j].compareTo(array[smallest])<0) { smallest=j; } } swap(array,i,smallest); } } } 四 Shell排序 package algorithms;
/** * @author yovn */ public class ShellSorter<E extends Comparable<E>> extends Sorter<E> { /* (non-Javadoc) * Our delta value choose 2^k-1,2^(k-1)-1,  .7,3,1.* complexity is O(n^1.5) * @see algorithms.Sorter#sort(E[], int, int) */ @Override public void sort(E[] array, int from, int len) { //1.calculate the first delta value; int value=1; while((value+1)*2<len) { value=(value+1)*2-1; } for(int delta=value;delta>=1;delta=(delta+1)/2-1) { for(int i=0;i<delta;i++) { modify_insert_sort(array,from+i,len-i,delta); } } } private final void modify_insert_sort(E[] array, int from, int len,int delta) { if(len<=1)return; E tmp=null; for(int i=from+delta;i<from+len;i+=delta) { tmp=array[i]; int j=i; for(;j>from;j-=delta) { if(tmp.compareTo(array[j-delta])<0) { array[j]=array[j-delta]; } else break; } array[j]=tmp; } } }
package algorithms;
/** * @author yovn * */ public class QuickSorter<E extends Comparable<E>> extends Sorter<E> { /* (non-Javadoc) * @see algorithms.Sorter#sort(E[], int, int) */ @Override public void sort(E[] array, int from, int len) { q_sort(array,from,from+len-1); } private final void q_sort(E[] array, int from, int to) { if(to-from<1)return; int pivot=selectPivot(array,from,to); pivot=partion(array,from,to,pivot); q_sort(array,from,pivot-1); q_sort(array,pivot+1,to); } private int partion(E[] array, int from, int to, int pivot) { E tmp=array[pivot]; array[pivot]=array[to];//now to's position is available while(from!=to) { while(from<to&&array[from].compareTo(tmp)<=0)from++; if(from<to) { array[to]=array[from];//now from's position is available to--; } while(from<to&&array[to].compareTo(tmp)>=0)to--; if(from<to) { array[from]=array[to];//now to's position is available now from++; } } array[from]=tmp; return from; } private int selectPivot(E[] array, int from, int to) { return (from+to)/2; } } |
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