#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
static int longestPalindromicSubstring(const string &s) {
const int n = static_cast<int>(s.size());
if (n == 0)
return 0;
int best = 1;
for (int c = 0; c < n; ++c) {
int l = c, r = c;
while (l >= 0 && r < n && s[l] == s[r]) {
best = max(best, r - l + 1);
--l;
++r;
}
l = c;
r = c + 1;
while (l >= 0 && r < n && s[l] == s[r]) {
best = max(best, r - l + 1);
--l;
++r;
}
}
return best;
}
static string wordFromIndex(long long idx, int n) {
string s(n, 'A');
for (int pos = 0; pos < n; ++pos) {
int bit = static_cast<int>((idx >> (n - 1 - pos)) & 1);
s[pos] = bit ? 'P' : 'A';
}
return s;
}
static void calculateBig(int n, int k) {
if (k < 4) {
cout << "NIE\n";
return;
}
const int numA = k - 1;
if (numA < 0 || numA > n) {
cout << "NIE\n";
return;
}
for (int i = 0; i < numA; ++i)
cout << 'A';
const char pat[] = "APAPPA";
const int plen = 6;
const int rest = n - numA;
for (int i = 0; i < rest; ++i)
cout << pat[i % plen];
cout << '\n';
}
static void enumerateSmall(int n, int k) {
const long long total = 1LL << n;
for (long long i = 0; i < total; ++i) {
const string w = wordFromIndex(i, n);
if (longestPalindromicSubstring(w) == k) {
cout << w << '\n';
return;
}
}
cout << "NIE\n";
}
int main() {
int t;
cin >> t;
while (t-- > 0) {
int n, k;
cin >> n >> k;
if (n > 8)
calculateBig(n, k);
else
enumerateSmall(n, k);
}
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | #include <algorithm> #include <iostream> #include <string> using namespace std; static int longestPalindromicSubstring(const string &s) { const int n = static_cast<int>(s.size()); if (n == 0) return 0; int best = 1; for (int c = 0; c < n; ++c) { int l = c, r = c; while (l >= 0 && r < n && s[l] == s[r]) { best = max(best, r - l + 1); --l; ++r; } l = c; r = c + 1; while (l >= 0 && r < n && s[l] == s[r]) { best = max(best, r - l + 1); --l; ++r; } } return best; } static string wordFromIndex(long long idx, int n) { string s(n, 'A'); for (int pos = 0; pos < n; ++pos) { int bit = static_cast<int>((idx >> (n - 1 - pos)) & 1); s[pos] = bit ? 'P' : 'A'; } return s; } static void calculateBig(int n, int k) { if (k < 4) { cout << "NIE\n"; return; } const int numA = k - 1; if (numA < 0 || numA > n) { cout << "NIE\n"; return; } for (int i = 0; i < numA; ++i) cout << 'A'; const char pat[] = "APAPPA"; const int plen = 6; const int rest = n - numA; for (int i = 0; i < rest; ++i) cout << pat[i % plen]; cout << '\n'; } static void enumerateSmall(int n, int k) { const long long total = 1LL << n; for (long long i = 0; i < total; ++i) { const string w = wordFromIndex(i, n); if (longestPalindromicSubstring(w) == k) { cout << w << '\n'; return; } } cout << "NIE\n"; } int main() { int t; cin >> t; while (t-- > 0) { int n, k; cin >> n >> k; if (n > 8) calculateBig(n, k); else enumerateSmall(n, k); } return 0; } |
English