7种排序算法（java）——第四遍

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package com.luojie;/** *  * @author Brandon 练习排序算法 */public class SortUtil {    public static int totalNum = 12;    static int initNum[] = new int[totalNum];    public static void main(String[] args) {        for (int i = 0; i < totalNum; i++) {            initNum[i] = (int) (Math.random() * 100);        }        printNum(initNum);        System.out.println("++++++++++++++++++++++++++++");        sortAlgorithm7(initNum);        printNum(initNum);    }    // 冒泡排序    public static void sortAlgorithm1(int initNum[]) {        int temp = -1;        for (int i = 0; i < initNum.length; i++) {            for (int j = 0; j < initNum.length - i - 1; j++) {                if (initNum[j] > initNum[j + 1]) {                    temp = initNum[j];                    initNum[j] = initNum[j + 1];                    initNum[j + 1] = temp;                }            }        }    }    // 选择排序    public static void sortAlgorithm2(int initNum[]) {        int max = 0;        int temp = -1;        for (int i = initNum.length - 1; i >= 0; i--) {            max = 0;            for (int j = 0; j <= i; j++) {                if (initNum[j] > initNum[max]) {                    max = j;                }            }            temp = initNum[i];            initNum[i] = initNum[max];            initNum[max] = temp;        }    }    // 插入排序，插入之前有序的队列中    public static void sortAlgorithm3(int initNum[]) {        int temp = 0;        int j = 0;        for (int i = 1; i < initNum.length; i++) {            temp = initNum[i];            j = i;            while (j > 0 && initNum[j - 1] > temp) {                initNum[j] = initNum[j - 1];                j--;            }            initNum[j] = temp;        }    }    // 希尔排序,直接在插入排序的基础上加一个步长就可以了    public static void sortAlgorithm4(int initNum[]) {        int temp = 0;        int j = 0;        for (int g = initNum.length / 2; g > 0; g = g / 2) {            for (int i = g; i < initNum.length; i += g) {                temp = initNum[i];                j = i;                while (j > 0 && initNum[j - g] > temp) {                    initNum[j] = initNum[j - g];                    j -= g;                }                initNum[j] = temp;            }        }    }    // 快速排序，快速定位某个数字的具体位置，分制法    public static void sortAlgorithm5(int initNum[]) {        quickSort(initNum, 0, initNum.length - 1);    }    public static void quickSort(int initNum[], int left, int right) {        if (left < right) {            int low = left;            int high = right;            int temp = initNum[left];            while (low < high) {                while (low < high && initNum[high] >= temp) {// 注意中间的那个等号，不然会产生死循环最后走不出来                    high--;                }                initNum[low] = initNum[high];                while (low < high && initNum[low] <= temp) {                    low++;                }                initNum[high] = initNum[low];            }            initNum[high] = temp;            quickSort(initNum, left, low - 1);            quickSort(initNum, low + 1, right);        }    }    // 堆排序，重要的是那个辅助方法，将一个数字插入大顶堆中    public static void sortAlgorithm6(int initNum[]) {        int temp = 0;        // 第一步：生成堆        for (int i = initNum.length / 2 - 1; i >= 0; i--) {            insertMethed(initNum, i, initNum.length - 1);        }        for (int j = initNum.length - 1; j >= 0; j--) {            temp = initNum[j];            initNum[j] = initNum[0];            initNum[0] = temp;            insertMethed(initNum, 0, j);        }        // 第二步：循环交换，在循环中将其新加入堆数字进行排序    }    // 辅助方法    public static void insertMethed(int initNum[], int startNode, int endNode) {        if (startNode < endNode) {            int leftNode = startNode * 2 + 1;            int rightNode = startNode * 2 + 2;            int maxNode = startNode;            int temp = 0;            if (leftNode < endNode && initNum[leftNode] > initNum[maxNode]) {                maxNode = leftNode;            }            if (rightNode < endNode && initNum[rightNode] > initNum[maxNode]) {                maxNode = rightNode;            }            if (maxNode != startNode) {                temp = initNum[maxNode];                initNum[maxNode] = initNum[startNode];                initNum[startNode] = temp;            }            insertMethed(initNum, leftNode, endNode);            insertMethed(initNum, rightNode, endNode);        }    }    // 归并排序,关键点是将两个有序数组合并成为一个有序数组    public static void sortAlgorithm7(int intNum[]) {        recursionMethed(initNum, 0, initNum.length - 1);    }    // 递归    public static void recursionMethed(int initNum[], int left, int right) {        int temp = (left + right) / 2;        if (left < right) {            recursionMethed(initNum, left, temp);            recursionMethed(initNum, temp + 1, right);            mergeMethed(initNum, left, temp, right);        }    }    // 合并方法,只适合相邻堆两个有序堆数组    public static void mergeMethed(int initNum[], int start, int middle, int end) {        int low1 = start;        int low2 = middle + 1;        int k = 0;        int initTemp[] = new int[end - start + 1];        while (low1 <= middle && low2 <= end) {            if (initNum[low1] <= initNum[low2]) {                initTemp[k] = initNum[low1];                low1++;                k++;            } else {                initTemp[k] = initNum[low2];                low2++;                k++;            }        }        while (low1 <= middle && low2 > end) {            initTemp[k] = initNum[low1];            low1++;            k++;        }        while (low1 > middle && low2 <= end) {            initTemp[k] = initNum[low2];            low2++;            k++;        }        for (int i = 0; i < initTemp.length; i++, start++) {            initNum[start] = initTemp[i];        }    }    public static void printNum(int initNum[]) {        for (int i = 0; i < initNum.length; i++) {            System.out.println(initNum[i]);        }    }}
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