結果
問題 | No.13 囲みたい! |
ユーザー | T101010101 |
提出日時 | 2024-07-14 18:10:54 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
WA
|
実行時間 | - |
コード長 | 26,662 bytes |
コンパイル時間 | 5,110 ms |
コンパイル使用メモリ | 311,600 KB |
実行使用メモリ | 6,944 KB |
最終ジャッジ日時 | 2024-07-14 18:11:01 |
合計ジャッジ時間 | 6,484 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge3 |
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テストケース
テストケース表示入力 | 結果 | 実行時間 実行使用メモリ |
---|---|---|
testcase_00 | AC | 2 ms
6,820 KB |
testcase_01 | AC | 1 ms
6,816 KB |
testcase_02 | AC | 2 ms
6,816 KB |
testcase_03 | WA | - |
testcase_04 | AC | 3 ms
6,940 KB |
testcase_05 | AC | 2 ms
6,944 KB |
testcase_06 | WA | - |
testcase_07 | AC | 3 ms
6,944 KB |
testcase_08 | AC | 3 ms
6,940 KB |
testcase_09 | WA | - |
testcase_10 | AC | 2 ms
6,940 KB |
testcase_11 | AC | 2 ms
6,944 KB |
testcase_12 | AC | 2 ms
6,944 KB |
testcase_13 | AC | 1 ms
6,944 KB |
testcase_14 | AC | 2 ms
6,944 KB |
testcase_15 | WA | - |
ソースコード
#pragma region Macros#pragma GCC optimize("O3,unroll-loops")#pragma GCC target("sse,sse2,sse3,ssse3,sse4,fma,abm,mmx,avx,avx2,popcnt")#include <bits/extc++.h>// #include <atcoder/all>// using namespace atcoder;using namespace std;using namespace __gnu_pbds;// #include <boost/multiprecision/cpp_dec_float.hpp>// #include <boost/multiprecision/cpp_int.hpp>// namespace mp = boost::multiprecision;// using Bint = mp::cpp_int;// using Bdouble = mp::number<mp::cpp_dec_float<256>>;// Bdouble Beps = 0.00000000000000000000000000000001; // 1e-32// const bool equals(Bdouble a, Bdouble b) { return mp::fabs(a - b) < Beps; }#define pb emplace_back#define int ll#define endl '\n'#define sqrt __builtin_sqrtl#define cbrt __builtin_cbrtl#define hypot __builtin_hypotl#define next asdnext#define prev asdprevusing ll = long long;using ld = long double;const ld PI = acosl(-1);const int INF = 1 << 30;const ll INFL = 1LL << 61;const int MOD = 998244353;// const int MOD = 1000000007;const ld EPS = 1e-10;const bool equals(ld a, ld b) { return fabs((a) - (b)) < EPS; }const vector<int> dx = {0, 1, 0, -1, 1, 1, -1, -1}; // → ↓ ← ↑ ↘ ↙ ↖ ↗const vector<int> dy = {1, 0, -1, 0, 1, -1, -1, 1};#define EC intstruct Edge {int from, to;EC cost;Edge() : from(-1), to(-1), cost(-1) {}Edge(int to, EC cost) : to(to), cost(cost) {}Edge(int from, int to, EC cost) : from(from), to(to), cost(cost) {}bool operator ==(const Edge& e) {return this->from == e.from && this->to == e.to && this->cost == e.cost;}bool operator !=(const Edge& e) {return this->from != e.from or this->to != e.to or this->cost != e.cost;}bool operator <(const Edge& e) { return this->cost < e.cost; }bool operator >(const Edge& e) { return this->cost > e.cost; }};chrono::system_clock::time_point start;__attribute__((constructor))void constructor() {ios::sync_with_stdio(false);cin.tie(nullptr);cout << fixed << setprecision(10);start = chrono::system_clock::now();}random_device seed_gen;mt19937_64 rng(seed_gen());uniform_int_distribution<int> dist_x(0, 1e9);struct RNG {unsigned Int() {return dist_x(rng);}unsigned Int(unsigned l, unsigned r) {return dist_x(rng) % (r - l + 1) + l;}ld Double() {return ld(dist_x(rng)) / 1e9;}} rnd;namespace bit_function {using i64 = ll;// using i64 = uint64_t;// bit演算, x==0の場合は例外処理した方がよさそう. 区間は [l, r)i64 lrmask(int l, int r) { return (1LL << r) - (1LL << l); }i64 sub_bit(i64 x, int l, int r) { i64 b = x & ((1LL << r) - (1LL << l)); return b >> l; } // r溢れ可i64 bit_width(i64 x) { return 64 - __builtin_clzll(x) + (x == 0); }i64 popcount(i64 x) { return __builtin_popcountll(x); }i64 popcount(i64 x, int l, int r) { return __builtin_popcountll(sub_bit(x, l, r)); }i64 unpopcount(i64 x) { return bit_width(x) - __builtin_popcountll(x); }i64 unpopcount(i64 x, int l, int r) { return r - l - __builtin_popcountll(sub_bit(x, l, r)); }bool is_pow2(i64 x) { return __builtin_popcountll(x) == 1; } // xが負のときは常にfalsebool is_pow4(i64 x) { return __builtin_popcount(x) == 1 && __builtin_ctz(x) % 2 == 0; }int top_bit(i64 x) { return 63 - __builtin_clzll(x);} // 2^kの位 (x > 0)int bot_bit(i64 x) { return __builtin_ctzll(x);} // 2^kの位 (x > 0)int next_bit(i64 x, int k) { // upper_boundx >>= (k + 1);int pos = k + 1;while (x > 0) {if (x & 1) return pos;x >>= 1;pos++;}return -1;}int prev_bit(i64 x, int k) {// k = min(k, bit_width(x)); ?int pos = 0;while (x > 0 && pos < k) {if (x & 1) {if (pos < k) return pos;}x >>= 1;pos++;}return -1;}int kth_bit(i64 x, int k) { // kは1-indexedint pos = 0, cnt = 0;while (x > 0) {if (x & 1) {cnt++;if (cnt == k) return pos;}x >>= 1;pos++;}return -1;}i64 MSB(i64 x) { if (x == 0) return 0; return 1LL << (63 - __builtin_clzll(x)); } // maski64 LSB(i64 x) { return (x & -x); } // maskint countl_zero(i64 x) { return __builtin_clzll(x); }int countl_one(i64 x) {i64 ret = 0, k = 63 - __builtin_clzll(x);while (k != -1 && (x & (1LL << k))) { k--; ret++; }return ret;}int countr_zero(i64 x) { return __builtin_ctzll(x); } // x==0のとき64が返ることに注意int countr_one(i64 x) { int ret = 0; while (x & 1) { x >>= 1; ret++; } return ret; }int floor_log2(i64 x) { if (x == 0) return 0; return 63 - __builtin_clzll(x); } // top_bitint ceil_log2(i64 x) { if (x == 0) return 0; return 64 - __builtin_clzll(x - 1); }i64 bit_floor(i64 x) { if (x == 0) return 0; return 1LL << (63 - __builtin_clzll(x)); } // MSBi64 bit_ceil(i64 x) { if (x == 0) return 0; return 1LL << (64 - __builtin_clzll(x - 1)); }i64 rotl(i64 x, int k) { // 有効bit内でrotate. オーバーフロー注意i64 w = bit_width(x); k %= w;return ((x << k) | (x >> (w - k))) & ((1LL << w) - 1);}// i64 rotl(i64 x, i64 l, i64 m, i64 r) {}i64 rotr(i64 x, int k) {i64 w = bit_width(x); k %= w;return ((x >> k) | (x << (w - k))) & ((1LL << w) - 1);}// i64 rotr(i64 x, i64 l, i64 m, i64 r) {}i64 bit_reverse(i64 x) { // 有効bit内で左右反転i64 r = 0, w = bit_width(x);for (i64 i = 0; i < w; i++) r |= ((x >> i) & 1) << (w - i - 1);return r;}// i64 bit_reverse(i64 x, int l, int r) {}bool is_palindrome(i64 x) { return x == bit_reverse(x); }bool is_palindrome(i64 x, int l, int r) { i64 b = sub_bit(x, l, r); return b == bit_reverse(b); }i64 concat(i64 a, i64 b) { return (a << bit_width(b)) | b; } // オーバーフロー注意i64 erase(i64 x, int l, int r) { return x >> r << l | x & ((1LL << l) - 1); } // [l, r) をカットi64 hamming(i64 a, i64 b) { return __builtin_popcountll(a ^ b); }i64 hamming(i64 a, i64 b, int l, int r) { return __builtin_popcountll(sub_bit(a, l, r) ^ sub_bit(b, l, r)); }i64 compcount(i64 x) { return (__builtin_popcountll(x ^ (x >> 1)) + (x & 1)) / 2; }i64 compcount2(i64 x) { return compcount(x & (x >> 1)); } // 長さ2以上の連結成分の個数i64 adjacount(i64 x) { return __builtin_popcountll(x & (x >> 1)); } // 隣接する1のペアの個数i64 next_combination(i64 x) {i64 t = x | (x - 1); return (t + 1) | (((~t & -~t) - 1) >> (__builtin_ctzll(x) + 1));}} using namespace bit_function;namespace util_function {namespace Std = std;__int128_t POW(__int128_t x, int n) {__int128_t ret = 1;assert(n >= 0);if (x == 1 or n == 0) ret = 1;else if (x == -1 && n % 2 == 0) ret = 1;else if (x == -1) ret = -1;else if (n % 2 == 0) {assert(x < INFL);ret = POW(x * x, n / 2);} else {assert(x < INFL);ret = x * POW(x, n - 1);}return ret;}int per(int x, int y) { // x = qy + r (0 <= r < y) を満たすqassert(y != 0);if (x >= 0 && y > 0) return x / y;if (x >= 0 && y < 0) return x / y - (x % y < 0);if (x < 0 && y < 0) return x / y + (x % y < 0);return x / y - (x % y < 0); // (x < 0 && y > 0)}int mod(int x, int y) { // x = qy + r (0 <= r < y) を満たすrassert(y != 0);return x - y * per(x, y);} // https://yukicoder.me/problems/no/2781int floor(int x, int y) { // (ld)x / y 以下の最大の整数assert(y != 0);if (y < 0) x = -x, y = -y;return x >= 0 ? x / y : (x + 1) / y - 1;}int ceil(int x, int y) { // (ld)x / y 以上の最小の整数assert(y != 0);if (y < 0) x = -x, y = -y;return x > 0 ? (x - 1) / y + 1 : x / y;}int round(int x, int y) { // (ld)(x/y)を小数点第1位について四捨五入assert(y != 0);return (x * 2 + y) / (y * 2);}int round(int x, int y, int k) { // (ld)(x/y)を10^kの位に関して四捨五入assert(y != 0 && k >= 0);if (k == 0) return (x * 2 + y) / (y * 2);x /= y * POW(10, k - 1);if (x % 10 >= 5) return (x + 10 - x % 10) * POW(10, k - 1);return x * POW(10, k - 1);}int round2(int x, int y) { // 五捨五超入 // 未verifyassert(y != 0);if (y < 0) y = -y, x = -x;int z = x / y;if ((z * 2 + 1) * y <= y * 2) z++;return z;}ld round(ld x, int k) { // xを10^kの位に関して四捨五入. to_string(x, k)優先// x += EPS;ld d = pow(10, -k);return Std::round(x * d) / d;}ld floor(ld x, int k) { // xを10^kの位に関してflooring// x += EPS;ld d = pow(10, -k);return Std::floor(x * d) / d; // 未verify}ld ceil(ld x, int k) { // xを10^kの位に関してceiling// x -= EPS;ld d = pow(10, -k);return Std::ceil(x * d) / d; // 未verify}// int kth(int x, int y, int k) { // x / yの10^kの位の桁// }int floor(ld x, ld y) { // 誤差対策TODOassert(!equals(y, 0));return Std::floor(x / y);// floor(x) = ceil(x - 1) という話も}int ceil(ld x, ld y) { // 誤差対策TODO // ceil(p/q) = -floor(-(p/q))らしいassert(!equals(y, 0));return Std::ceil(x / y);// ceil(x) = floor(x + 1)}int perl(ld x, ld y) { // x = qy + r (0 <= r < y, qは整数) を満たす q// 未verify. 誤差対策TODO. EPS外してもいいかも。assert(!equals(y, 0));if (x >= 0 && y > 0) return Std::floor(x / y)+EPS;if (x >= 0 && y < 0) return -Std::floor(x / fabs(y));if (x < 0 && y < 0) return Std::floor(x / y) + (x - Std::floor(x/y)*y < -EPS);return Std::floor(x / y) - (x - Std::floor(x/y)*y < -EPS); // (x < 0 && y > 0)}ld modl(ld x, ld y) { // x = qy + r (0 <= r < y, qは整数) を満たす r// 未verify. 誤差対策TODO. -0.0が返りうる。assert(!equals(y, 0));if (x >= 0) return x - fabs(y)*fabs(per(x, y));return x - fabs(y)*floor(x, fabs(y));}int seisuu(ld x) { return (int)x; } // 整数部分. 誤差対策TODOint modf(ld x) {if (x < 0) return ceill(x);else return floorl(x);}// 正なら+EPS, 負なら-EPSしてから、文字列に直して小数点以下を捨てる?int seisuu(int x, int y) {assert(y != 0);return x / y;}int seisuu(ld x, ld y) { // 誤差対策TODOassert(!equals(y, 0));return (int)(x / y);}template <class T> pair<T, T> max(const pair<T, T> &a, const pair<T, T> &b) {if (a.first > b.first or a.first == b.first && a.second > b.second) return a;return b;}template <class T> pair<T, T> min(const pair<T, T> &a, const pair<T, T> &b) {if (a.first < b.first or a.first == b.first && a.second < b.second) return a;return b;}template <class T> bool chmax(T &a, const T& b) {if (a < b) { a = b; return true; } return false;}template <class T> bool chmin(T &a, const T& b) {if (a > b) { a = b; return true; } return false;}template <class T> T mid(T a, T b, T c) { // 誤差対策TODOreturn a + b + c - max({a, b, c}) - min({a, b, c});}template <class T> void Sort(T &a, T &b, bool rev = false) {if (rev == false) if (a > b) swap(a, b);else if (b > a) swap(b, a);}template <typename T, typename... Args>void Sort(T& a, T& b, T& c, Args&... args) {vector<T> vec = {a, b, c, args...};sort(vec.begin(), vec.end());auto it = vec.begin();a = *it++; b = *it++; c = *it++;int dummy[] = { (args = *it++, 0)... };static_cast<void>(dummy);}istream &operator >>(istream &is, __int128_t& x) {string S; is >> S;__int128_t ret = 0;int f = 1;if (S[0] == '-') f = -1;for (int i = 0; i < S.length(); i++)if ('0' <= S[i] && S[i] <= '9')ret = ret * 10 + S[i] - '0';x = ret * f;return (is);}ostream &operator <<(ostream &os, __int128_t x) {ostream::sentry s(os);if (s) {__uint128_t tmp = x < 0 ? -x : x;char buffer[128]; char *d = end(buffer);do {--d; *d = "0123456789"[tmp % 10]; tmp /= 10;} while (tmp != 0);if (x < 0) { --d; *d = '-'; }int len = end(buffer) - d;if (os.rdbuf()->sputn(d, len) != len) os.setstate(ios_base::badbit);}return os;}__int128_t stoll(string &S) {__int128_t ret = 0; int f = 1;if (S[0] == '-') f = -1;for (int i = 0; i < S.length(); i++)if ('0' <= S[i] && S[i] <= '9') ret = ret * 10 + S[i] - '0';return ret * f;}__int128_t gcd(__int128_t a, __int128_t b) { return b ? gcd(b, a % b) : a; }__int128_t lcm(__int128_t a, __int128_t b) {return a / gcd(a, b) * b;// lcmが__int128_tに収まる必要あり}string to_string(ld x, int k) { // xの小数第k位までをstring化するassert(k >= 0);stringstream ss;ss << setprecision(k + 2) << x;string s = ss.str();if (s.find('.') == string::npos) s += '.';int pos = s.find('.');for (int i = 0; k >= (int)s.size() - 1 - pos; i++) s += '0';s.pop_back();if (s.back() == '.') s.pop_back();return s;// stringstream ss; // 第k+1位を四捨五入して第k位まで返す// ss << setprecision(k + 1) << x;// string s = ss.str();// if (s.find('.') == string::npos) s += '.';// int pos = s.find('.');// for (int i = 0; k > (int)s.size() - 1 - pos; i++) s += '0';// if (s.back() == '.') s.pop_back();// return s;}string to_string(__int128_t x) {string ret = "";if (x < 0) { ret += "-"; x *= -1; }while (x) { ret += (char)('0' + x % 10); x /= 10; }reverse(ret.begin(), ret.end());return ret;}string to_string(char c) { string s = ""; s += c; return s; }} using namespace util_function;struct custom_hash {static uint64_t splitmix64(uint64_t x) {x += 0x9e3779b97f4a7c15;x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;x = (x ^ (x >> 27)) * 0x94d049bb133111eb;return x ^ (x >> 31);}size_t operator()(uint64_t x) const {static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();return splitmix64(x + FIXED_RANDOM);}};template<class T> size_t HashCombine(const size_t seed,const T &v) {return seed^(hash<T>()(v)+0x9e3779b9+(seed<<6)+(seed>>2));}template<class T,class S> struct hash<pair<T,S>>{size_t operator()(const pair<T,S> &keyval) const noexcept {return HashCombine(hash<T>()(keyval.first), keyval.second);}};template<class T> struct hash<vector<T>>{size_t operator()(const vector<T> &keyval) const noexcept {size_t s=0;for (auto&& v: keyval) s=HashCombine(s,v);return s;}};template<int N> struct HashTupleCore{template<class Tuple> size_t operator()(const Tuple &keyval) const noexcept{size_t s=HashTupleCore<N-1>()(keyval);return HashCombine(s,get<N-1>(keyval));}};template <> struct HashTupleCore<0>{template<class Tuple> size_t operator()(const Tuple &keyval) const noexcept{ return 0; }};template<class... Args> struct hash<tuple<Args...>>{size_t operator()(const tuple<Args...> &keyval) const noexcept {return HashTupleCore<tuple_size<tuple<Args...>>::value>()(keyval);}};template<typename T>class Compress { // 試験運用, バグったらTをintにするpublic:int sz = 0;// gp_hash_table<T, int, custom_hash> Z;// gp_hash_table<int, T, custom_hash> UZ;unordered_map<T, int> Z; // 元の値 -> 圧縮した値unordered_map<int, T> UZ; // 圧縮した値 -> 元の値Compress(const vector<T> &V, T base = 0) {this->sz = base;set<T> s(V.begin(), V.end());for (T x : s) {this->Z[x] = this->sz;this->UZ[this->sz] = x;this->sz++;}}Compress(const vector<T> &V1, const vector<T> &V2, T base = 0) {this->sz = base;vector<T> V3 = V2;V3.insert(V3.end(), V1.begin(), V1.end());set<T> s(V3.begin(), V3.end());for (T x : s) {this->Z[x] = this->sz;this->UZ[this->sz] = x;this->sz++;}}Compress(const vector<T> &V1, const vector<T> &V2, const vector<T> &V3, T base = 0) {this->sz = base;vector<T> V4 = V1;V4.insert(V4.end(), V2.begin(), V2.end());V4.insert(V4.end(), V3.begin(), V3.end());set<T> s(V4.begin(), V4.end());for (T x : s) {this->Z[x] = this->sz;this->UZ[this->sz] = x;this->sz++;}}Compress(const vector<T> &V1, const vector<T> &V2,const vector<T> &V3, const vector<T> &V4, T base = 0) {this->sz = base;vector<T> V5 = V1;V5.insert(V5.end(), V2.begin(), V2.end());V5.insert(V5.end(), V3.begin(), V3.end());V5.insert(V5.end(), V4.begin(), V4.end());set<T> s(V5.begin(), V5.end());for (T x : s) {this->Z[x] = this->sz;this->UZ[this->sz] = x;this->sz++;}}vector<int> zip(const vector<T> &V) {vector<int> ret(V.size());for (int i = 0; i < (int)V.size(); i++) {ret[i] = Z[V[i]];}return ret;}vector<T> unzip(const vector<int> &V) {vector<T> ret(V.size());for (int i = 0; i < (int)V.size(); i++) {ret[i] = UZ[V[i]];}return ret;}int size() { return sz; }T encode(int x) { return Z[x]; }int decode(T x) {if (UZ.find(x) == UZ.end()) return -1; // xが元の配列に存在しないときreturn UZ[x];}};class UnionFind {public:UnionFind() = default;UnionFind(int N) : par(N), sz(N, 1) {iota(par.begin(), par.end(), 0);}int root(int x) {if (par[x] == x) return x;return (par[x] = root(par[x]));}bool unite(int x, int y) {int rx = root(x);int ry = root(y);if (rx == ry) return false;if (sz[rx] < sz[ry]) swap(rx, ry);sz[rx] += sz[ry];par[ry] = rx;return true;}bool issame(int x, int y) { return (root(x) == root(y)); }int size(int x) { return sz[root(x)]; }vector<vector<int>> groups(int N) {vector<vector<int>> G(N);for (int x = 0; x < N; x++) {G[root(x)].push_back(x);}G.erase( remove_if(G.begin(), G.end(),[&](const vector<int>& V) { return V.empty(); }), G.end());return G;}private:vector<int> par, sz;};template<typename T> struct BIT {int N; // 要素数vector<T> bit[2]; // データの格納先BIT(int N_, int x = 0) {N = N_ + 1;bit[0].assign(N, 0); bit[1].assign(N, 0);if (x != 0) {for (int i = 0; i < N; i++) add(i, x);}}BIT(const vector<T> &A) {N = A.size() + 1;bit[0].assign(N, 0); bit[1].assign(N, 0);for (int i = 0; i < (int)A.size(); i++) add(i, A[i]);}void add_sub(int p, int i, T x) {while (i < N) { bit[p][i] += x; i += (i & -i); }}void add(int l, int r, T x) {add_sub(0, l + 1, -x * l); add_sub(0, r + 1, x * r);add_sub(1, l + 1, x); add_sub(1, r + 1, -x);}void add(int i, T x) { add(i, i + 1, x); }T sum_sub(int p, int i) {T ret = 0;while (i > 0) { ret += bit[p][i]; i -= (i & -i); }return ret;}T sum(int i) { return sum_sub(0, i) + sum_sub(1, i) * i; }T sum(int l, int r) { return sum(r) - sum(l); }T get(int i) { return sum(i, i + 1); }void set(int i, T x) { T s = get(i); add(i, -s + x); }};template<int mod> class Modint {public:int val = 0;Modint(int x = 0) { while (x < 0) x += mod; val = x % mod; }Modint(const Modint &r) { val = r.val; }Modint operator -() { return Modint(-val); } // 単項Modint operator +(const Modint &r) { return Modint(*this) += r; }Modint operator +(const int &q) { Modint r(q); return Modint(*this) += r; }Modint operator -(const Modint &r) { return Modint(*this) -= r; }Modint operator -(const int &q) { Modint r(q); return Modint(*this) -= r; }Modint operator *(const Modint &r) { return Modint(*this) *= r; }Modint operator *(const int &q) { Modint r(q); return Modint(*this) *= r; }Modint operator /(const Modint &r) { return Modint(*this) /= r; }Modint operator /(const int &q) { Modint r(q); return Modint(*this) /= r; }Modint& operator ++() { val++; if (val >= mod) val -= mod; return *this; } // 前置Modint operator ++(signed) { ++*this; return *this; } // 後置Modint& operator --() { val--; if (val < 0) val += mod; return *this; }Modint operator --(signed) { --*this; return *this; }Modint &operator +=(const Modint &r) { val += r.val; if (val >= mod) val -= mod; return *this; }Modint &operator +=(const int &q) { Modint r(q); val += r.val; if (val >= mod) val -= mod; return *this; }Modint &operator -=(const Modint &r) { if (val < r.val) val += mod; val -= r.val; return *this; }Modint &operator -=(const int &q) { Modint r(q); if (val < r.val) val += mod; val -= r.val; return *this; }Modint &operator *=(const Modint &r) { val = val * r.val % mod; return *this; }Modint &operator *=(const int &q) { Modint r(q); val = val * r.val % mod; return *this; }Modint &operator /=(const Modint &r) {int a = r.val, b = mod, u = 1, v = 0;while (b) {int t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v);}val = val * u % mod; if (val < 0) val += mod;return *this;}Modint &operator /=(const int &q) {Modint r(q); int a = r.val, b = mod, u = 1, v = 0;while (b) {int t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v);}val = val * u % mod; if (val < 0) val += mod;return *this;}bool operator ==(const Modint& r) { return this -> val == r.val; }bool operator <(const Modint& r) { return this -> val < r.val; }bool operator >(const Modint& r) { return this -> val > r.val; }bool operator !=(const Modint& r) { return this -> val != r.val; }friend istream &operator >>(istream &is, Modint& x) {int t; is >> t; x = t; return (is);}friend ostream &operator <<(ostream &os, const Modint& x) {return os << x.val;}};using mint = Modint<MOD>;mint modpow(const mint &x, int n) {if (n < 0) return (mint)1 / modpow(x, -n); // 未verifyassert(n >= 0);if (n == 0) return 1;mint t = modpow(x, n / 2);t = t * t;if (n & 1) t = t * x;return t;}int modpow(__int128_t x, int n, int mod) {assert(n >= 0 && mod > 0); // TODO: n <= -1__int128_t ret = 1;while (n > 0) {if (n % 2 == 1) ret = ret * x % mod;x = x * x % mod;n /= 2;}return ret;}// int modinv(__int128_t x, int mod) { //// assert(mod > 0);// // assert(x > 0);// if (x == 1 or x == 0) return 1;// return mod - modinv(mod % x, mod) * (mod / x) % mod;// }vector<mint> _fac, _finv, _inv;void COMinit(int N) {_fac.resize(N + 1); _finv.resize(N + 1); _inv.resize(N + 1);_fac[0] = _fac[1] = 1; _finv[0] = _finv[1] = 1; _inv[1] = 1;for (int i = 2; i <= N; i++) {_fac[i] = _fac[i-1] * mint(i);_inv[i] = -_inv[MOD % i] * mint(MOD / i);_finv[i] = _finv[i - 1] * _inv[i];}}mint FAC(int N) {if (N < 0) return 0; return _fac[N];}mint COM(int N, int K) {if (N < K) return 0; if (N < 0 or K < 0) return 0;return _fac[N] * _finv[K] * _finv[N - K];}mint PERM(int N, int K) {if (N < K) return 0; if (N < 0 or K < 0) return 0;return _fac[N] * _finv[N - K];}mint NHK(int N, int K) { // initのサイズに注意if (N == 0 && K == 0) return 1;return COM(N + K - 1, K);}#pragma endregionint H, W;bool isvalid(int x, int y) {if (x >= 0 && x < H && y >= 0 && y < W) return true;else return false;}signed main() {cin >> W >> H;vector<vector<int>> A(H, vector<int>(W));for (int i = 0; i < H; i++) {for (int j = 0; j < W; j++) {cin >> A[i][j];}}bool ans = false;vector<vector<int>> done(H, vector<int>(W));for (int sx = 0; sx < H; sx++) {for (int sy = 0; sy < W; sy++) {if (done[sx][sy]) continue;// (現在の座標, 直前の座標)queue<tuple<int, int, int, int>> qu;done[sx][sy] = true;qu.emplace(sx, sy, -1, -1);while (qu.size()) {auto [i, j, pi, pj] = qu.front();qu.pop();for (int k = 0; k < 4; k++) {int ni = i + dx[k];int nj = j + dy[k];if (!isvalid(ni, nj)) continue;if (A[ni][nj] == A[i][j]) continue;if (ni == pi && nj == pj) continue;if (done[ni][nj]) {ans = true;break;}done[ni][nj] = true;qu.emplace(ni, nj, i, j);}if (ans) break;}if (ans) break;}if (ans) break;}if (!ans) cout << "possible" << endl;else cout << "impossible" << endl;}