算法基础--基本排序算法总结·
总结了插入、冒泡、快速排序、选择排序、堆排序、基数排序、归并排序7种排序算法
public class CSort { //插入 public void d_insort(int[] a) { if (a.Length < 1) return; int i, j, t; for (i = 1; i < a.Length; i++) { t = a[i]; for (j = i - 1; j >=0 && t < a[j];j-- )//把大于t的元素后移 { a[j + 1] = a[j]; } a[j + 1] = t;//插入t } } //冒泡 public void BubbleSort(int[] a) { if (a.Length < 1) return; int i, j, t; i = a.Length; while (i > 1) {//每次循环把最大的数放入有序序列的第一个 for (j = 0; j < i - 1; j++) { if (a[j + 1] < a[j]) { t = a[j]; a[j] = a[j + 1]; a[j + 1] = t; } } i--; } } //快排 public void quickSort(int[] a) { if (a.Length < 1) return; qSort(a, 0, a.Length - 1); } private void qSort(int[] a,int left,int right) {//从left到right进行按left索引值进行分块//递归到1 if (right - left < 1) return; int i = left, j = right; int x = a[i]; while (i < j) { while ((a[j] >=x) && (i<j)) j --; a[i] = a[j]; while ((a[i] <= x) && (j > i)) i++; a[j] = a[i]; } a[i] = x; qSort(a, left, i - 1); qSort(a, i + 1, right); } //选择排序 public void SelectSort(int[] a) { if (a.Length < 1) return; sSort(a, 0); } private void sSort(int[] a, int start) {//从start开始选择最小与start交换 if (start == a.Length) return; int index = start; for (int i = start+1; i < a.Length; i++) { if (a[index]> a[i]) { index = i; } } int t = a[start]; a[start] = a[index]; a[index] = t; sSort(a, start + 1); } //堆排序 public void heapSort(int[] a) { int t; int n=a.Length; for(int i=n/2;i>=0;i--)//初始堆 SIFT(a,i,n); for (int i = n - 1; i >= 0; i--)//排序 {//交换 t = a[0]; a[0] = a[i]; a[i] = t; SIFT(a, 0, i - 1);//剩下的堆重新构造 } } private void SIFT(int[] a, int i, int n) {//构造堆 /逆堆 int j, T; T = a[i]; j = 2 * i; while (j < n) { if ((j < n) && (a[j] < a[j + 1])) j++; if (T < a[j]) { a[i] = a[j]; i = j; j = 2 * i; } else { j = n; } a[i] = T; } } //基数排序 public void rSort(int[] a) { if (a.Length < 1) return; // rl_sort(a,1,3); rr_sort(a, 0,a.Length-1,3); } private void rl_sort(int[] a,int d,int k) {//lsd 低位到高位 if (d > k) return; int begin = 0, end = a.Length-1; const int radix = 10; int[] count = new int[radix];//基数右索引 int[] bucket = new int[a.Length];//缓存 for (int i = begin; i <= end; i++) { count[get(a[i], d)]++;//每个关键码的个数 } for (int i = 1; i < radix; i++) { count[i] = count[i] + count[i - 1];//累加个数，对应右边界索引 } for (int i = end; i >=begin; i--) { int j = get(a[i], d);//求关键码 bucket[count[j] - 1] = a[i];//放入对应的索引位置 count[j]--;//放一个右索引左移一 } for (int i = begin, j = 0; i <= end; i++, j++) { a[i] = bucket[j]; } rl_sort(a,d + 1,k);// 高位one more try } private void rr_sort(int[] a,int begin,int end,int d) {//MSD//高位到低位 const int radix = 10; int[] count = new int[radix];//基数索引 int[] bucket = new int[a.Length];//缓存 for (int i = begin; i <= end; i++) { count[get(a[i], d)]++; } for (int i = 1; i < radix; i++) { count[i] = count[i] + count[i - 1]; } for (int i = end; i >= begin; i--) { int j = get(a[i], d); bucket[count[j] - 1] = a[i]; count[j]--;//循环减完了就变左边界了 } for (int i = begin, j = 0; i <= end; i++, j++) { a[i] = bucket[j]; } for (int i = 1; i < radix; i++)//0不用循环，高位必须是1开始 { int p1 = begin+ count[i-1]; int p2 = begin+count[i] - 1; if (p1 < p2 && d > 1) { rr_sort(a, p1, p2, d - 1); } } } private int get(int a,int reg) { int[] d = { 1, 1, 10, 100,1000 }; return (a / d[reg]) % 10; } //归并排序 public void mergeSort(int[] a) { if (a.Length < 1) return; mSortPass(a, 1); } private void mSortPass(int[] a,int len) { if (a.Length<len) return; int s = 0; while (s + 2 * len-1 < a.Length) { mSort(a, s, s + len, s + 2 * len - 1); s = s + 2 * len; } int c = 0; if (s - 2 * len < 0) { s = 0; c = len; } else { s = s - 2 * len; c = s + 2 * len; } if (s< a.Length - 1)//最后一个序列 { mSort(a, s, c, a.Length - 1); } mSortPass(a, 2 * len); } private void mSort(int[] a,int s1,int s2,int l2) { int tlen=l2 - s1 + 1; int[] temp = new int[tlen]; int i = s1, j = s2, k = 0; while (i < s2 && j <= l2)//把小的添加到缓冲 { if (a[i] <= a[j]) { temp[k] = a[i]; i++; k++; } else { temp[k] = a[j]; j++; k++; } } //剩下的添加到缓冲 while (i < s2) { temp[k] = a[i]; i++; k++; } while (j <= l2) { temp[k] = a[j]; j++; k++; } Array.Copy(temp, 0, a, s1, tlen);//复制 } }
