PAT (Advanced Level) 1098. Insertion or Heap Sort (25)

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

const int maxn=200;
int a[maxn],b[maxn],n;

int main()
{
    memset(b,-1,sizeof b);
    scanf("%d",&n);
    for(int i=1; i<=n; i++) scanf("%d",&a[i]);
    for(int i=1; i<=n; i++) scanf("%d",&b[i]);

    int flag=1;

    int p=n+1;
    for(int i=2; i<=n; i++)
        if(b[i]<b[i-1])
        {
            p=i;
            break;
        }

    for(int i=p; i<=n; i++)
    {
        if(a[i]==b[i]) continue;
        else flag=0;
    }

    if(flag==1)
    {
        printf("Insertion Sort\n");
        if(p==n+1) p=n;
        sort(a+1,a+p+1);
        for(int i=1; i<=p; i++)
        {
            printf("%d",a[i]);
            if(i<n) printf(" ");
            else printf("\n");
        }
        for(int i=p+1; i<=n; i++)
        {
            printf("%d",a[i]);
            if(i<n) printf(" ");
            else printf("\n");
        }
    }
    else
    {
        printf("Heap Sort\n");
        sort(a+1,a+1+n);
        for(int i=n; i>=1; i--)
        {
            if(a[i]==b[i]) p=i;
            else break;
        }

        swap(b[1],b[p-1]);

        int i=1;;
        while(1)
        {
            if(2*i<p-1&&2*i+1<p-1)
            {
                if(b[i]<max(b[2*i],b[2*i+1]))
                {

                    if(b[2*i]>b[2*i+1])
                    {
                        swap(b[2*i],b[i]);
                        i=2*i;
                    }
                    else
                    {
                        swap(b[2*i+1],b[i]);
                        i=2*i+1;
                    }
                }
                else break;
            }
            else if(2*i<p-1)
            {
                if(b[i]<b[2*i])
                {
                    swap(b[2*i],b[i]);
                    i=2*i;
                }
            }
            else break;

        }
        for(int i=1; i<=n; i++)
        {
            printf("%d",b[i]);
            if(i<n) printf(" ");
            else printf("\n");
        }
    }

    return 0;
}