C语言对数组从小到大排序去重

可以使用快速排序或归并排序对数组排序，然后依次遍历数组，将重复的元素删除即可。下面是示例代码：

#include <stdio.h>

void quick_sort(int arr[], int left, int right) {
    if (left >= right) return;

    int i = left, j = right, pivot = arr[left];
    while (i < j) {
        while (i < j && arr[j] >= pivot) j--;
        arr[i] = arr[j];
        while (i < j && arr[i] <= pivot) i++;
        arr[j] = arr[i];
    }
    arr[i] = pivot;
    quick_sort(arr, left, i - 1);
    quick_sort(arr, i + 1, right);
}

void remove_duplicates(int arr[], int size) {
    for (int i = 0; i < size - 1; i++) {
        if (arr[i] == arr[i + 1]) {
            for (int j = i + 1; j < size - 1; j++) {
                arr[j] = arr[j + 1];
            }
            size--;
            i--;
        }
    }
}

int main() {
    int arr[] = {1, 3, 5, 2, 4, 3, 2, 6, 5};
    int size = sizeof(arr) / sizeof(arr[0]);

    // sort the array
    quick_sort(arr, 0, size - 1);

    // remove duplicates
    remove_duplicates(arr, size);

    // print the result
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}