java 各种排序算法实现

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package com.meteor.algorithm;/** * sortMethods * Created by Meteor on 2016/3/26. */public class SortMethods {    /**     * Simple insertionSort(插入排序)     * @param arr the array that need to sort     * @param <T> type parameter     */    public static <T extends Comparable<? super T>> void insertionSort(T [] arr){        int j;        for(int p = 1;p < arr.length;p++){            T tmp = arr[p];            for(j = p;j > 0 && tmp.compareTo(arr[j-1])<0;j--){                arr[j] = arr[j-1];            }            arr[j] = tmp;        }    }    /**     * quicksort(快速排序)     * @param arr an array of Comparable items     * @param left the left-most index of the subarray     * @param rignt the right-most index of the subarray     * @param <T>     */    public static <T extends Comparable<? super T>> void quicksort(T[] arr,int left,int rignt){        int dp;        if(left < rignt){            dp = partition(arr,left,rignt);            quicksort(arr,left,dp-1);            quicksort(arr,dp+1,rignt);        }    }    private static <T extends Comparable<? super T>> int partition(T[] arr,int left,int right ){        T centerValue = arr[left];        while (left < right){            while (left < right && (arr[right].compareTo(centerValue))>0){                right--;            }            if(left<right){                arr[left++] = arr[right];            }            while (left < right && (arr[left].compareTo(centerValue))<0){                left++;            }            if(left<right){                arr[right--] = arr[left];            }        }        arr[left] = centerValue;        return left;    }    /**     * shellSort(希尔排序)     * @param arr     * @param <T>     */    public static <T extends Comparable<? super T>> void shellSort(T [] arr){        int j;        for(int gap = arr.length/2;gap > 0;gap /= 2){            for(int i = gap;i<arr.length;i++){                T tmp = arr[i];                for(j = i;j >= gap && tmp.compareTo(arr[j-gap]) < 0; j -=gap){                    arr[j] = arr[j-gap];                }                arr[j] = tmp;            }        }    }    /**     * Mergesort algotithm(归并排序)     * @param arr an array of Comparable items     * @param <T>     */    public static <T extends Comparable<? super T>> void mergeSort(T[] arr){        T[] tempArr = (T[]) new Comparable[arr.length];        mergeSort(arr,tempArr,0,arr.length-1);    }    /**     * Internal method that makes recursive calls     * @param arr an array of Comparable items     * @param tempArr an array to place the merged result     * @param left the left-most index of the subarray     * @param right the right-most index of the subarray     * @param <T>     */    private static <T extends  Comparable<? super T>>    void mergeSort(T[] arr,T[] tempArr,int left,int right){        if(left < right){            int center = (left+right)/2;            mergeSort(arr,tempArr,left,center);            mergeSort(arr,tempArr,center+1,right);            merge(arr,tempArr,left,center+1,right);        }    }    /**     * Internal method that merges two sorted halves of a subarray     * @param arr a array of Comparable items     * @param tempArr an array to place the merged result     * @param leftPos the left-most index of the subarray     * @param rightPos the index of the start of the second half     * @param rightEnd the right-most index of the subarray     * @param <T>     */    private static <T extends Comparable<? super T>> void merge(T [] arr,T [] tempArr, int leftPos, int rightPos,int rightEnd){        int leftEnd = rightPos -1;        int tmpPos = leftPos;        int numElements = rightEnd - leftPos + 1;        //Main loop        while (leftPos <= leftEnd && rightPos <= rightEnd){            if(arr[leftPos].compareTo(arr[rightPos]) <= 0){                tempArr[tmpPos++] = arr[leftPos++];            }else{                tempArr[tmpPos++] = arr[rightPos++];            }        }        //copy rest of first half        while (leftPos <= leftEnd){            tempArr[tmpPos++] = arr[leftPos++];        }        //copy rest of right half        while (rightPos<=rightEnd){            tempArr[tmpPos++] = arr[rightPos++];        }        //copy tempArr back        for (int i = 0; i < numElements ; i++,rightEnd--) {            arr[rightEnd] = tempArr[rightEnd];        }    }    public static void main(String[] args) {        Integer [] arr = {10,19,12,14,9,6,3,45};        //SortMethods.insertionSort(arr);        SortMethods.shellSort(arr);        for (Integer tem:arr){            System.out.print(tem+"; ");        }    }}

package com.meteor.algorithm;

/**
* sortMethods
* Created by Meteor on 2016/3/26.
*/
public class SortMethods {

/** * Simple insertionSort(插入排序) * @param arr the array that need to sort * @param <T> type parameter */public static <T extends Comparable<? super T>> void insertionSort(T [] arr){    int j;    for(int p = 1;p < arr.length;p++){        T tmp = arr[p];        for(j = p;j > 0 && tmp.compareTo(arr[j-1])<0;j--){            arr[j] = arr[j-1];        }        arr[j] = tmp;    }}/** * quicksort(快速排序) * @param arr an array of Comparable items * @param left the left-most index of the subarray * @param rignt the right-most index of the subarray * @param <T> */public static <T extends Comparable<? super T>> void quicksort(T[] arr,int left,int rignt){    int dp;    if(left < rignt){        dp = partition(arr,left,rignt);        quicksort(arr,left,dp-1);        quicksort(arr,dp+1,rignt);    }}private static <T extends Comparable<? super T>> int partition(T[] arr,int left,int right ){    T centerValue = arr[left];    while (left < right){        while (left < right && (arr[right].compareTo(centerValue))>0){            right--;        }        if(left<right){            arr[left++] = arr[right];        }        while (left < right && (arr[left].compareTo(centerValue))<0){            left++;        }        if(left<right){            arr[right--] = arr[left];        }    }    arr[left] = centerValue;    return left;}/** * shellSort(希尔排序) * @param arr * @param <T> */public static <T extends Comparable<? super T>> void shellSort(T [] arr){    int j;    for(int gap = arr.length/2;gap > 0;gap /= 2){        for(int i = gap;i<arr.length;i++){            T tmp = arr[i];            for(j = i;j >= gap && tmp.compareTo(arr[j-gap]) < 0; j -=gap){                arr[j] = arr[j-gap];            }            arr[j] = tmp;        }    }}/** * Mergesort algotithm(归并排序) * @param arr an array of Comparable items * @param <T> */public static <T extends Comparable<? super T>> void mergeSort(T[] arr){    T[] tempArr = (T[]) new Comparable[arr.length];    mergeSort(arr,tempArr,0,arr.length-1);}/** * Internal method that makes recursive calls * @param arr an array of Comparable items * @param tempArr an array to place the merged result * @param left the left-most index of the subarray * @param right the right-most index of the subarray * @param <T> */private static <T extends  Comparable<? super T>>void mergeSort(T[] arr,T[] tempArr,int left,int right){    if(left < right){        int center = (left+right)/2;        mergeSort(arr,tempArr,left,center);        mergeSort(arr,tempArr,center+1,right);        merge(arr,tempArr,left,center+1,right);    }}/** * Internal method that merges two sorted halves of a subarray * @param arr a array of Comparable items * @param tempArr an array to place the merged result * @param leftPos the left-most index of the subarray * @param rightPos the index of the start of the second half * @param rightEnd the right-most index of the subarray * @param <T> */private static <T extends Comparable<? super T>> void merge(T [] arr,T [] tempArr, int leftPos, int rightPos,int rightEnd){    int leftEnd = rightPos -1;    int tmpPos = leftPos;    int numElements = rightEnd - leftPos + 1;    //Main loop    while (leftPos <= leftEnd && rightPos <= rightEnd){        if(arr[leftPos].compareTo(arr[rightPos]) <= 0){            tempArr[tmpPos++] = arr[leftPos++];        }else{            tempArr[tmpPos++] = arr[rightPos++];        }    }    //copy rest of first half    while (leftPos <= leftEnd){        tempArr[tmpPos++] = arr[leftPos++];    }    //copy rest of right half    while (rightPos<=rightEnd){        tempArr[tmpPos++] = arr[rightPos++];    }    //copy tempArr back    for (int i = 0; i < numElements ; i++,rightEnd--) {        arr[rightEnd] = tempArr[rightEnd];    }}public static void main(String[] args) {    Integer [] arr = {10,19,12,14,9,6,3,45};    //SortMethods.insertionSort(arr);    SortMethods.shellSort(arr);    for (Integer tem:arr){        System.out.print(tem+"; ");    }}

}

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