1035. 插入与归并(25)

10
3 1 2 8 7 5 9 4 6 0
1 2 3 7 8 5 9 4 6 0

Insertion Sort
1 2 3 5 7 8 9 4 6 0

10
3 1 2 8 7 5 9 4 0 6
1 3 2 8 5 7 4 9 0 6

Merge Sort
1 2 3 8 4 5 7 9 0 6

解析：学习的本质和目的是善假于物，如果一切都是从0做起那在这个世界上是生存不下去的，牛顿都说过，“站在巨人的肩上”，所以学习算法一样，你可以用现有的算法和工具解决问题，至于深层次的问题的理解是一个漫长的边实践边思考的过程，记得一个数学老师指点学生怎样学习微积分，大致意思是说，“只要懂得基本的概念就可以了，剩下的功夫就是做题做题做题，在实践中理解更深的概念，如果上来就往底层挖，结果就是陷入一个知识黑洞中而再也出不来了，学习的本质就是两个，认识工具，熟练使用工具”。

代码：

#include <stdio.h>
#include <stdlib.h>int cmp(const void *a, const void *b)
{return *(int *)a - *(int *)b;
}int is_same(int *a, int *b, int N)
{int i;int flag = 1;for (i = 0; i < N; i++){if (a[i] != b[i]){flag = 0;break;}}return flag;
}void print(int *arr, int N)
{int loopk;for (loopk = 0; loopk < N; loopk++){printf("%d%s", arr[loopk], loopk == N-1 ? "" : " ");}printf("\n");
}int main()
{int N;int input[2<<7], part_sort[2<<7], sorted[2<<7];int loopi, loopj, loopk;int flag = 1;int once = 0;scanf("%d", &N);for (loopi = 0; loopi < N; loopi++){scanf("%d", input+loopi);sorted[loopi] = *(input+loopi);}for (loopi = 0; loopi < N; loopi++){scanf("%d", part_sort+loopi);}for (loopi = 0; loopi < N-1; loopi++){if (part_sort[loopi] > part_sort[loopi+1]){break;}}for (loopj = loopi+1; loopj < N; loopj++){if (part_sort[loopj] != input[loopj]){flag = 0;break;}}#if 0loopi = N - 1;while (loopi >= 0 && input[loopi]==part_sort[loopi]){loopi--;}qsort(sorted, loopi+1, sizeof(int), cmp);for (loopj = 0; loopj <= loopi; loopj++){if (sorted[loopj] != part_sort[loopj]){flag = 0;break;}}#endifif (flag == 1){printf("Insertion Sort\n");qsort(sorted, loopi+2, sizeof(int), cmp);print(sorted, N);}else{printf("Merge Sort\n");for (loopi = 1; loopi <= 20*N; loopi *= 2){once = is_same(input, part_sort, N);loopj = 0;	// [loopj*loopi, (loopj+1)*loopi-1] partion to be sortwhile ((loopj+1) * loopi < N){qsort(input+loopj*loopi, loopi, sizeof(int), cmp);loopj++;}if (loopj * loopi < N){qsort(input+loopj*loopi, N-loopj*loopi, sizeof(int), cmp);}if (once == 1){print(input, N);break;}}}return 0;
}