C 语言外部排序算法：对大数组进行排序

#include <stdio.h>\n#include <stdlib.h>\n\n#define MAX_NUMBERS 10000000\n#define CHUNK_SIZE 1000\n#define BUFFER_SIZE 100\n\n// 内部排序函数\nvoid internalSort(int* numbers, int size) {\n // 使用快速排序等算法对数组进行排序\n // ...\n}\n\n// 外部排序函数\nvoid externalSort() {\n // 打开输入文件和输出文件\n FILE* input = fopen("input.txt", "w");\n FILE* output = fopen("output.txt", "w");\n\n // 定义要排序的数组\n int numbers[] = {51, 49, 39, 46, 38, 29, 14, 61, 15, 30, 1, 48, 52, 3, 63, 27, 4, 13, 89, 24, 46, 58, 33, 76};\n int size = sizeof(numbers) / sizeof(numbers[0]);\n\n // 将数组写入输入文件\n fwrite(numbers, sizeof(int), size, input);\n fclose(input);\n\n // 读取输入文件并分割成多个小文件\n int* buffer = (int*)malloc(CHUNK_SIZE * sizeof(int));\n int fileIndex = 0;\n input = fopen("input.txt", "r");\n while (!feof(input)) {\n // 读取CHUNK_SIZE个整数到缓冲区\n int count = fread(buffer, sizeof(int), CHUNK_SIZE, input);\n\n // 对缓冲区中的整数进行内部排序\n internalSort(buffer, count);\n\n // 将排序后的缓冲区写入一个新的小文件中\n char filename[20];\n sprintf(filename, "chunk%d.txt", fileIndex);\n FILE* chunk = fopen(filename, "w");\n fwrite(buffer, sizeof(int), count, chunk);\n fclose(chunk);\n\n fileIndex++;\n }\n fclose(input);\n free(buffer);\n\n // 创建优先级队列和输出缓冲区\n int* priorityQueue = (int*)malloc(BUFFER_SIZE * sizeof(int));\n int* outputBuffer = (int*)malloc(BUFFER_SIZE * sizeof(int));\n int outputSize = 0;\n\n // 打开所有小文件并初始化读取指针\n FILE** chunks = (FILE**)malloc(fileIndex * sizeof(FILE*));\n int* pointers = (int*)malloc(fileIndex * sizeof(int));\n for (int i = 0; i < fileIndex; i++) {\n char filename[20];\n sprintf(filename, "chunk%d.txt", i);\n chunks[i] = fopen(filename, "r");\n pointers[i] = 0;\n }\n\n // 选择排序并置换\n while (1) {\n // 清空优先级队列\n int queueSize = 0;\n\n // 从每个小文件中读取一个元素放入优先级队列中\n for (int i = 0; i < fileIndex; i++) {\n if (pointers[i] < CHUNK_SIZE) {\n fseek(chunks[i], pointers[i] * sizeof(int), SEEK_SET);\n fread(&(priorityQueue[queueSize]), sizeof(int), 1, chunks[i]);\n queueSize++;\n pointers[i]++;\n }\n }\n\n // 如果队列为空，则所有元素已经读取完毕，退出循环\n if (queueSize == 0) {\n break;\n }\n\n // 选择队列中的最小元素\n int minIndex = 0;\n for (int i = 1; i < queueSize; i++) {\n if (priorityQueue[i] < priorityQueue[minIndex]) {\n minIndex = i;\n }\n }\n\n // 将最小元素放入输出缓冲区\n outputBuffer[outputSize] = priorityQueue[minIndex];\n outputSize++;\n\n // 如果输出缓冲区已满，则将缓冲区写入输出文件\n if (outputSize == BUFFER_SIZE) {\n fwrite(outputBuffer, sizeof(int), BUFFER_SIZE, output);\n outputSize = 0;\n }\n }\n\n // 将剩余的输出缓冲区写入输出文件\n if (outputSize > 0) {\n fwrite(outputBuffer, sizeof(int), outputSize, output);\n }\n\n // 关闭文件和释放内存\n fclose(output);\n for (int i = 0; i < fileIndex; i++) {\n fclose(chunks[i]);\n char filename[20];\n sprintf(filename, "chunk%d.txt", i);\n remove(filename);\n }\n free(priorityQueue);\n free(outputBuffer);\n free(chunks);\n free(pointers);\n}\n\nint main() {\n externalSort();\n return 0;\n