基数排序（代码+注释)

#include <stdio.h>
#include <stdlib.h>// 获取数组中的最大值
int GetMax(int* a, int n) {int max = a[0];for (int i = 1; i < n; i++) {if (a[i] > max) {max = a[i];}}return max;
}// 对数组按照某个位数进行计数排序
void CountingSortForRadix(int* a, int n, int exp) {int* output = (int*)malloc(n * sizeof(int));int count[10] = {0}; // 因为是按位排序，只有 0-9 共 10 个数字// 统计每个位上的出现次数for (int i = 0; i < n; i++) {int digit = (a[i] / exp) % 10;count[digit]++;}// 计算累积计数for (int i = 1; i < 10; i++) {count[i] += count[i - 1];}// 按当前位排序，将数据放入输出数组for (int i = n - 1; i >= 0; i--) {int digit = (a[i] / exp) % 10;output[count[digit] - 1] = a[i];count[digit]--;}// 将排序结果复制回原数组for (int i = 0; i < n; i++) {a[i] = output[i];}free(output);
}// 基数排序主函数
void RadixSort(int* a, int n) {int max = GetMax(a, n); // 找到数组中最大值for (int exp = 1; max / exp > 0; exp *= 10) {CountingSortForRadix(a, n, exp);}
}// 测试函数
int main() {int a[] = {170, 45, 75, 90, 802, 24, 2, 66};int n = sizeof(a) / sizeof(a[0]);printf("Before sorting: ");for (int i = 0; i < n; i++) {printf("%d ", a[i]);}printf("\n");RadixSort(a, n);printf("After sorting: ");for (int i = 0; i < n; i++) {printf("%d ", a[i]);}printf("\n");return 0;
}

测试结果