▶ 学习了双调排序，参考（https://blog.csdn.net/xbinworld/article/details/76408595）
● 使用 CPU 排序的代码
1 #include <stdio.h> 2 3 #define LENGTH 1024 4 #define ASCENDING 1 5 #define DESCENDING 0 6 7 int a[LENGTH]; 8 9 void compare(int i, int j, int dir) 10 { 11 if (dir == (a[i]>a[j])) 12 { 13 int h = a[i]; 14 a[i] = a[j]; 15 a[j] = h; 16 } 17 } 18 19 void bitonicMerge01(int lo, int cnt, int dir)// 先再大跨度（半区间长）上调整元素，再递归地在小跨度上进行相同的调整 20 { 21 if (cnt > 1) 22 { 23 int k = cnt / 2; 24 for (int i = lo; i < lo + k; i++) 25 compare(i, i + k, dir); 26 bitonicMerge01(lo, k, dir); 27 bitonicMerge01(lo + k, k, dir); 28 } 29 } 30 31 void bitonicSort01(int lo, int cnt, int dir)// 先递归地要求小跨度区间依次排成 “升↗降↘升↗降↘” 再在较大跨度上进行合并 32 { 33 if (cnt > 1) 34 { 35 int k = cnt / 2; 36 bitonicSort01(lo, k, ASCENDING); 37 bitonicSort01(lo + k, k, DESCENDING); 38 bitonicMerge01(lo, cnt, dir); 39 } 40 } 41 42 void bitonicMerge02(int l, int r, const int dir) 43 { 44 if (r - l > 0) 45 { 46 int stride = (r - l) / 2 + 1; 47 for (int i = l; i < l + stride; i++) 48 compare(i, i + stride, dir); 49 bitonicMerge02(l, l + stride - 1, dir); 50 bitonicMerge02(l + stride, r, dir); 51 } 52 } 53 54 void bitonicSort02(int l, int r, const int dir) 55 { 56 if (r - l > 0) 57 { 58 int rNew = l + (r - l) / 2; 59 bitonicSort02(l, rNew, ASCENDING); 60 bitonicSort02(rNew + 1, r, DESCENDING); 61 bitonicMerge02(l, r, dir); 62 } 63 } 64 65 void bitonicMerge03(int l, int r, const int dir) 66 { 67 if (r - l > 1) 68 { 69 int stride = (r - l) / 2; 70 for (int i = l; i < l + stride; i++) 71 compare(i, i + stride, dir); 72 bitonicMerge03(l, l + stride, dir); 73 bitonicMerge03(l + stride, r, dir); 74 } 75 } 76 77 void bitonicSort03(int l, int r, const int dir) 78 { 79 if (r - l > 1) 80 { 81 int rNew = l + (r - l) / 2; 82 bitonicSort03(l, rNew, ASCENDING); 83 bitonicSort03(rNew, r, DESCENDING); 84 bitonicMerge03(l, r, dir); 85 } 86 } 87 88 int main() 89 { 90 int i, error; 91 srand(97); 92 for (i = 0; i < LENGTH; a[i++] = rand()); 93 94 printf(" "); 95 for (i = 0; i < LENGTH; i++) 96 { 97 printf("%5d,", a[i]); 98 if ((i + 1) % 10 == 0) 99 printf(" "); 100 } 101 102 //bitonicSort01(0, LENGTH, ASCENDING); // 使用起点和长度 103 //bitonicSort02(0, LENGTH - 1, ASCENDING); // 使用左端点和右端点（都包含） 104 bitonicSort03(0, LENGTH, ASCENDING); // 使用左端点和右端点（左包含右不包含） 105 106 printf(" "); 107 for (i = 0, error = -1; i < LENGTH; i++) 108 { 109 printf("%5d,", a[i]); 110 if (i < LENGTH - 1 && a[i] > a[i + 1]) 111 error = i; 112 if ((i + 1) % 10 == 0) 113 printf(" "); 114 } 115 if (error != -1) 116 printf(" error at i==%d, a[i]==%d, a[i+1]==%d", error, a[error], a[error + 1]); 117 118 getchar(); 119 return 0; 120 }
● 输出结果（临时改为排序 64 个元素，每行显示 16个）
355, 1738,17358,10050,26329,32242,15361,10484, 6442,24073,24274,32373,18693,32410,10489,26548, 21618,11292,16736, 2813,14168,26214, 3533,18194,25922,25449,31426,27518,28770,10781,31394,19238, 8663,22972, 20,23841,26411,28975,30636,24521,14624,10949, 1225,12818,24492,16427, 1465,22299, 14146,10905, 8996,22531,23379,13129,28327,30718,23061,26669,21695,28328,21891,18657,26089, 7321, 20, 355, 1225, 1465, 1738, 2813, 3533, 6442, 7321, 8663, 8996,10050,10484,10489,10781,10905, 10949,11292,12818,13129,14146,14168,14624,15361,16427,16736,17358,18194,18657,18693,19238,21618, 21695,21891,22299,22531,22972,23061,23379,23841,24073,24274,24492,24521,25449,25922,26089,26214, 26329,26411,26548,26669,27518,28327,28328,28770,28975,30636,30718,31394,31426,32242,32373,32410,