Ｃ言語　ALDS1_2_C　Stable Sort

#include <stdio.h>

typedef struct
{
    char mark;
    char num;
} Card;

static void swap(Card *a, Card *b)
{
    Card tmp = *a;
    *a = *b;
    *b = tmp;
}

static void print_array(Card array[], int array_len)
{
    for (int i = 0; i < array_len; i++)
    {
        printf("%c%c", array[i].mark, array[i].num);
        if (i != array_len - 1)
            printf(" ");
    }
    printf("\n");
}

/* 選択ソート */
static void selection_sort(Card A[], int N)
{
    int min_index;

    for (int i = 0; i < N; i++)
    {
        min_index = i;
        for (int j = i; j < N; j++)
            if (A[j].num < A[min_index].num)
                min_index = j;
        if (i != min_index)
            swap(&A[i], &A[min_index]);
    }
    print_array(A, N);
}

/* バブルソート */
static void bubble_sort(Card A[], int N)
{
    for (int i = 0; i < N; i++)
        for (int j = 0; j + 1 < N - i; j++)
            if (A[j].num > A[j + 1].num)
                swap(&A[j], &A[j + 1]);
    print_array(A, N);
}

/* 安定性判定(A[]には必ずバブルソート済みの配列を入れる) */
static void isStable(Card A[], Card B[], int N)
{
    for(int i = 0; i < N; i++)
        if(A[i].mark != B[i].mark){
            printf("Not stable\n");
            return;
        }
    printf("Stable\n");
    return;
}

int main(void)
{
    int N;
    char card[3];
    Card A[36];
    Card B[36];

    scanf("%d", &N);
    for (int i = 0; i < N; i++)
    {
        scanf("%s", card);
        A[i].mark = card[0];
        A[i].num = card[1];
        B[i] = A[i];
    }

    bubble_sort(A, N);
    isStable(A,A,N);
    selection_sort(B, N);
    isStable(A,B,N);
    return 0;
}