#include<bits/stdc++.h>
#define N 250

using namespace std;

string s[N];

int main()
{
	int n,k;
	cin >> n >> k;
	char k1=65,k2=97;
	for (int i=1;i<=n;i++)
	{
		if (k2==123)
		{
			k2=97;
			k1++;
		}
		s[i][0] = k1;
		s[i][1] = k2;
		k2++;
	}
	for (int i=1;i<=n-k+1;i++)
	{
		string str;
		cin >> str;
		if (str=="NO") s[i+k-1] = s[i];
	}
	for (int i=1;i<=n;i++)
		cout << s[i] << " ";
	cout << endl;
	return 0; 
}

这个代码RE了

for (int i=1;i<=n;i++)
{
	if (k2==123)
	{
		k2=97;
		k1++;
	}
	s[i][0] = k1;
	s[i][1] = k2;
	k2++;
}

是因为这段代码