PAT (Advanced Level) 1089. Insert or Merge (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()
{
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("Merge Sort\n");

int len=1;
while(1)
{
int pp=1;
while(1)
{
if(pp+len-1>n)
{
sort(a+pp,a+n+1);
break;
}
else
{
sort(a+pp,a+pp+len);
pp=pp+len;
}
}

int fail=0;
for(int i=1; i<=n; i++) if(a[i]!=b[i]) fail=1;

if(fail==0)
{
len=len*2;
int ppp=1;
while(1)
{
if(ppp+len-1>n)
{
sort(a+ppp,a+n+1);
break;
}
else
{
sort(a+ppp,a+ppp+len);
ppp=ppp+len;
}
}
for(int i=1;i<=n;i++)
{
printf("%d",a[i]);
if(i<n) printf(" ");
else printf("\n");
}
break;
}
len=len*2;
}
}

return 0;
}