排序算法总结

• 插入排序
  稳定排序， 复杂度 n^2

public static void insertSort(int []arr) {        int i = 0, j = 0, temp = 0;        for(i = 0; i < arr.length - 1; i++)            for(j = i + 1; j > 0; j--) {                if(arr[j] >= arr[j-1]) break;                temp = arr[j-1];                arr[j-1] = arr[j];                arr[j] = temp;            }    }

• 快速排序
  不稳定排序， 复杂度nlog(n)

public static void  swap(int indexOne, int indexTwo, int []arr) {        int temp = 0;        temp = arr[indexOne];        arr[indexOne] = arr[indexTwo];        arr[indexTwo] = temp;    }public static void quickSort(int start, int end, int []arr) {    if(start >= end) return;    int mid = arr[start], left = start + 1, right = end;    while(left < right) {        while(arr[right] >= mid && left < right) right--;        while(arr[left] <= mid && left < right) left++;        swap(left, right, arr);    }    if(arr[right] < mid) swap(start, right, arr);    else right--;    quickSort(start, right -1, arr);    quickSort(right + 1, end, arr);}

• 归并排序
  稳定排序，复杂度nlog(n)

public static void mergeSort(int arr[], int result[], int start, int end) {    if(start >= end) return;    int mid = (end - start) >> 1;    int start1 = start, end1 = start + mid;    int start2 = start + mid + 1, end2 = end;    mergeSort(arr, result, start1, end1);    mergeSort(arr, result, start2, end2);    int k = start;    while(start1 <= end1 && start2 <= end2) {        if(arr[start1] <= arr[start2]) result[k++] = arr[start1++];            else result[k++] = arr[start2++];    }    while(start1 <= end1) {        result[k++] = arr[start1++];    }    while(start2 <= end2) {        result[k++] = arr[start2++];    }    for(k = start; k <= end; k++) {        arr[k] = result[k];    }}