模拟。
#include <bits/stdc++.h>
using namespace std;
int n, k;
string s;
int main()
{
cin >> n >> k;
int tmp = 0;
while (n -- )
{
cin >> s;
if (tmp + s.size() > k)
{
tmp = s.size();
cout << endl << s;
}
else
{
if (tmp != 0) cout << " ";
tmp += s.size();
cout << s;
}
}
return 0;
}