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归并排序

查看归并段的层数

#include <stdio.h>
#include <math.h>

#define N 10
int arr[N] = {0, 9, 8, 7, 6, 5, 4, 3, 2, 1};
int depth = (int)log2(10-1)+2; // 递归深度计数器

void merge_sort(int l, int r) {
    if (r <= l) return;
    
    depth--; // 进入递归时增加深度
    int current_depth = depth; // 记录当前深度
    
    int mid = (l + r) >> 1;
    merge_sort(l, mid);
    merge_sort(mid + 1, r);
    
    int i = l, j = mid + 1;
    int len = 0;
    int tmp[N];
    while (i <= mid && j <= r) {
        if (arr[i] < arr[j]) 
            tmp[len++] = arr[i++];
        else 
            tmp[len++] = arr[j++];
    }
    while (i <= mid) tmp[len++] = arr[i++];
    while (j <= r) tmp[len++] = arr[j++];
    
    printf("第%d趟排序区间 [%d, %d]: ", current_depth, l, r);
    for (int i = l, j = 0; i <= r; i++, j++) {
        arr[i] = tmp[j];
        printf("%d ", arr[i]);
    }
    puts("");
    
    depth++; // 退出递归时减少深度
}

int main() {
//	printf("%d", (int)log2(N));
    merge_sort(1, 9);
    return 0;
}