voidswap(int *a,int *b)//交換兩個變數 { int temp = *a; *a = *b; *b = temp; } voidselection_sort(int arr[], int len) { int i,j; for (i = 0 ; i < len - 1 ; i++) { int min = i; for (j = i + 1; j < len; j++) //走訪未排序的元素 if (arr[j] < arr[min]) //找到目前最小值 min = j; //紀錄最小值 swap(&arr[min], &arr[i]); //做交換 } }
voidinsertion_sort(int arr[], int len){ int i,j,temp; for (i=1;i<len;i++){ temp = arr[i]; for (j=i;j>0 && arr[j-1]>temp;j--) arr[j] = arr[j-1]; arr[j] = temp; } }
希尔排序
希尔排序,也称递减增量排序算法,是插入排序的一种更高效的改进版本。希尔排序是非稳定排序算法。
希尔排序是基于插入排序的以下两点性质而提出改进方法的:
插入排序在对几乎已经排好序的数据操作时,效率高,即可以达到线性排序的效率
但插入排序一般来说是低效的,因为插入排序每次只能将数据移动一位
过程演示:
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voidshell_sort(int arr[], int len){ int gap, i, j; int temp; for (gap = len >> 1; gap > 0; gap = gap >> 1) for (i = gap; i < len; i++) { temp = arr[i]; for (j = i - gap; j >= 0 && arr[j] > temp; j -= gap) arr[j + gap] = arr[j]; arr[j + gap] = temp; } }
intmin(int x, int y){ return x < y ? x : y; } voidmerge_sort(int arr[], int len){ int* a = arr; int* b = (int*) malloc(len * sizeof(int)); int seg, start; for (seg = 1; seg < len; seg += seg) { for (start = 0; start < len; start += seg + seg) { int low = start, mid = min(start + seg, len), high = min(start + seg + seg, len); int k = low; int start1 = low, end1 = mid; int start2 = mid, end2 = high; while (start1 < end1 && start2 < end2) b[k++] = a[start1] < a[start2] ? a[start1++] : a[start2++]; while (start1 < end1) b[k++] = a[start1++]; while (start2 < end2) b[k++] = a[start2++]; } int* temp = a; a = b; b = temp; } if (a != arr) { int i; for (i = 0; i < len; i++) b[i] = a[i]; b = a; } free(b); }
voidswap(int *x, int *y){ int t = *x; *x = *y; *y = t; } voidquick_sort_recursive(int arr[], int start, int end){ if (start >= end) return; int mid = arr[end]; int left = start, right = end - 1; while (left < right) { while (arr[left] < mid && left < right) left++; while (arr[right] >= mid && left < right) right--; swap(&arr[left], &arr[right]); } if (arr[left] >= arr[end]) swap(&arr[left], &arr[end]); else left++; if (left) quick_sort_recursive(arr, start, left - 1); quick_sort_recursive(arr, left + 1, end); } voidquick_sort(int arr[], int len){ quick_sort_recursive(arr, 0, len - 1); }