已知不是内存错误

#include <bits/stdc++.h>
using namespace std;
const int N=2020;
char ans[N];
char c;
int k,len;
int main ()
{
	scanf ("%d\n",&k);
	
	while (1)
	{
		c=getchar();
		if (c>='a'&&c<='z')
		{
			c-='a';
			if (int(c)<k)
				c=c+26-k;
			else
				c=c-k;
			c+='a';
		}
		else if (c>='A'&&c<='Z')
		{
			c-='A';
			if (int(c)<k)
				c=c+26-k;
			else
				c=c-k;
			c+='A';
		}
		if (c=='\n')
			break;
		ans[++len]=c;
	}
	
	printf ("%s",ans+1);
	
	return 0;
}