java数据结构之常用排序算法

冒泡排序

private void maopao(int arr[]) {

    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr.length - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

选择排序

    private void xuanze(int[] arr) {
        for (int i = 0; i < arr.length; i++) {
            int min = arr[i];
            int x = -1;
            boolean b = false;
            for (int j = i; j < arr.length; j++) {
                if (arr[j] < min) {
                    b = true;
                    min = arr[j];
                    x = j;
                }
            }
            if (b) {
                int temp = arr[i];
                arr[i] = min;
                arr[x] = temp;
            }

        }
    }

插入排序

 1     private void charu(int[] arr2) {
 2         int[] arr = new int[arr2.length];
 3         for (int i = 0; i < arr2.length; i++) {
 4             arr[i] = arr2[i];
 5             for (int j = 0; j < i; j++) {
 6                 if (arr[i] >= arr[j] && arr[i] <= arr[j + 1]) {
 7                     arr = houyi(arr, j, i);
 8                 }
 9             }
10         }
11     }
12 
13     /**
14      * 指定位置后移
15      *
16      * @param arr
17      * @param j
18      * @param i
19      * @return
20      */
21     private int[] houyi(int[] arr, int j, int i) {
22         int temp = arr[i];
23         for (int k = i; k > j; k--) {
24             arr[k] = arr[k - 1];
25         }
26         arr[j] = temp;
27         return arr;
28     }

希尔排序

 1     /**
 2      * 希尔排序
 3      *
 4      * @param arr
 5      */
 6     private void xier(int[] arr) {
 7         for (int i = arr.length / 2; i > 0; i = i / 2) {
 8             for (int j = i; j < arr.length; j++) {
 9                 for (int k = j - i; k >= 0; k -= i) {
10                     if (arr[k] > arr[i + k]) {
11                         int temp = arr[k];
12                         arr[k] = arr[k + i];
13                         arr[k + i] = temp;
14                     }
15                 }
16             }
17         }
18     }

快速排序

 1     /**
 2      * 快速排序
 3      *
 4      * @param arr
 5      * @param left
 6      * @param right
 7      */
 8     private void kuaisu(int[] arr, int left, int right) {
 9         int l = left;
10         int r = right;
11         int pivot = arr[(left + right) / 2];
12         int temp = 0;
13         while (l < r) {
14             while (arr[l] < pivot) {//寻找左边第一个不小于pivot的索引
15                 l += 1;
16             }
17             while (arr[r] > pivot) {//寻找右边第一个不大于pivot的索引
18                 r -= 1;
19             }
20             if (l >= r) {
21                 break;
22             }
23             temp = arr[l];
24             arr[l] = arr[r];
25             arr[r] = temp;//左右位置的值互换
26             if (arr[l] == pivot) {
27                 r -= 1;
28             }
29             if (arr[r] == pivot) {
30                 l += 1;
31             }
32         }
33         if (l == r) {
34             l += 1;
35             r -= 1;
36         }
37         if (left < r) {
38             kuaisu(arr, left, r);
39         }
40         if (right > l) {
41             kuaisu(arr, l, right);
42         }
43     }

基数排序（桶排序）

 1  private static void radix(int[] arr) {
 2         int max=arr[0];
 3         for (int i = 1; i <arr.length ; i++) {
 4             if (arr[i]>max){
 5                 max=arr[i];
 6             }
 7         }
 8         int maxleng=(max+"").length();
 9         for (int i = 0,n=1; i <maxleng ;n*=10, i++) {
10             int[][] arr2=new int[10][arr.length];
11             int[] indexs=new int[10];
12             int index=0;
13             for (int j = 0; j <arr.length ; j++) {
14                 int yushu=arr[j]/n%10;
15                 arr2[yushu][indexs[yushu]]=arr[j];
16                 indexs[yushu]++;
17             }
18             for (int j = 0; j <arr2.length ; j++) {
19                 for (int a = 0; a <indexs[j] ; a++) {
20                         arr[index++]=arr2[j][a];
21                 }
22             }
23         }
24     }