hdu 5055 Bob and math problem

<span style="font-size:18px;">#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>

using namespace std;

int main()
{
int n,i;
int a[110],b[110];
while(scanf("%d",&n)==1)
{
int sum=0;
int flag;
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
if(a[i]!=0)
{
sum++;
}
}
if(n==1)
{
if(a[0]%2==1)
{
printf("%d\n",a[0]);
}
else
{
printf("-1\n");
}
continue;
}
sort(a,a+n);
for(i=0;i<n;i++)
{
if(a[i]%2==1)
{
flag=i;
break;
}
}
if(i==n||sum<=1)
{
printf("-1\n");
}
else
{
for(i=n-1;i>=0;i--)
{
if(i!=flag)
{
printf("%d",a[i]);
}
}
printf("%d\n",a[flag]);
}
}
return 0;
}
</span>

<span style="font-size:18px;">#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>

using namespace std;

int main()
{
int n,i;
int a[110],b[110];
while(scanf("%d",&n)==1)
{
int minn=10;
int sum=0;
int flag=0;
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
if(a[i]%2==1)
{
flag=1;
minn=min(minn,a[i]);
}
if(a[i]!=0)
{
sum++;
}
}
if(flag==0)
{
printf("-1\n");
continue;
}
if(n==1)
{
if(a[0]%2==1)
{
printf("%d\n",a[0]);
}
else
{
printf("-1\n");
}
continue;
}
if(sum<=1)
{
printf("-1\n");
continue;
}

int len=0;
int flag1=0;
for(i=0;i<n;i++)
{
if(a[i]==minn&&flag1==0)
{
flag1=1;
}
else
{
b[len++]=a[i];
}
}
sort(b,b+len);

int flag2=0;
for(i=len-1;i>=0;i--)
{
if(b[i]!=0)
{
printf("%d",b[i]);
flag2=1;
}
else if(flag2==1)
{
printf("%d",b[i]);
}

}
printf("%d\n",minn);
}
return 0;
}</span>