Language: C++

//#include <bits/stdc++.h>

#include <iostream>
#include <algorithm>

#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <cstring>
#include <string>
#include <utility>
#include <array>
#include <complex>
#include <valarray>

#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>


using namespace std;
#define int long long

typedef long long ll;
typedef unsigned long long ull;
//typedef unsigned __int128 HASH;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pullull;
typedef pair<ll,int> plli;
typedef pair<double,int> pdi;
typedef pair<long double, int> pdbi;
typedef pair<int,pii> pipii;
typedef pair<ll,pll> plpll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
typedef vector<vector<int>> mat;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()

const ll hmod1 = 999999937;
const ll hmod2 = 1000000000 + 9;
const int INF = 1<<30;
const ll INFLL = 1LL<<62;
const long double EPS = 1e-12;
const ll mod = 1000000000 + 7;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const long double pi = 3.141592653589793;

#define addm(X, Y) (X) = ((X) + ((Y) % mod) + mod) % mod
#define inside(y, x, h, w) (0 <= (y) && (y) < (h) && 0 <= (x) && (x) < (w)) ? true : false

//debug
#define DEBUG

#define DUMPOUT cout

#ifdef DEBUG
#define dump(...) DUMPOUT<<#__VA_ARGS__<<" :["<<__FUNCTION__<<":"<<__LINE__<<"]"<<endl; DUMPOUT<<"    "; dump_func(__VA_ARGS__)
#else
#define dump(...)
#endif

void dump_func() {DUMPOUT << endl;};

template <class Head, class... Tail> void dump_func(Head&& head, Tail&&... tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) == 0) DUMPOUT << " ";
    else DUMPOUT << ", ";
    dump_func(std::move(tail)...);
}

//ostream
template<typename T> ostream& operator << (ostream& os, vector<T>& vec) {
    os << "["; for (int i = 0; i<vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : ", "); os << "]";
    return os;
}

template<typename T, typename U> ostream& operator << (ostream& os, pair<T, U>& pair_var) {
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}

template<typename T, typename U> ostream& operator << (ostream& os, map<T, U>& map_var) {
    os << "[";
    for (auto itr = map_var.begin(); itr != map_var.end(); itr++) {
        os << "(" << itr->first << ", " << itr->second << ")"; itr++;  if(itr != map_var.end()) os << ", "; itr--;
    }
    os << "]";
    return os;
}

template<typename T> ostream& operator << (ostream& os, set<T>& set_var) {
    os << "[";
    for (auto itr = set_var.begin(); itr != set_var.end(); itr++) {
        os << *itr; ++itr; if(itr != set_var.end()) os << ", "; itr--;
    }
    os << "]";
    return os;
}

int h, w, k;
int dp[808][10];

int calc(int x) {
  int cnt = 0;
  int l = x - 1;
  int r = x + 1;
  rep(i, 1LL<<(w-1LL)) {
    vector<int> v;
    bool ok = false;
    rep(j, w-1) {
      if (i>>j & 1) {
        if (j == x) ok = true;
        v.push_back(j);
      }
    }
    if (!ok) continue;
    rep(j, v.size()) {
      if (v[j] == l || v[j] == r) ok = false;
    }
    if (!ok) continue;
    rep(j, max(0LL, v.size() - 1LL)) {
      if (v[j] + 1 == v[j + 1]) ok = false;
    }
    if (ok) cnt++;
  }
  return cnt;
}

int calc2(int l, int r) {
  int cnt = 0;
  rep(i, 1LL<<(w-1LL)) {
    bool ok = true;
    vector<int> v;
    rep(j, w-1) {
      if (i>>j & 1) {
        if (j == l || j == r) ok = false;
        v.push_back(j);
      }
    }
    if (!ok) continue;
    rep(j, max(0LL, v.size() - 1LL)) {
      if (v[j] + 1 == v[j + 1]) ok = false;
    }
    if (!ok) continue;
    cnt++;
  }
  return cnt;
}

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> h >> w >> k;
  dp[0][1] = 1;
  rep2(i, 1, h + 1)rep2(j, 1, w + 1) {
    if (j == 1) {
      addm(dp[i][j], dp[i - 1][j + 1] * calc(j - 1));
      //addm(dp[i][j], calc(j - 1));
      addm(dp[i][j], dp[i - 1][j] * calc2(-1, 0));
      //addm(dp[i][j], calc2(-1, 0));
    }
    else if (j == w) {
      addm(dp[i][j], dp[i - 1][j - 1] * calc(j - 2));
      //addm(dp[i][j], calc(j - 2));
      addm(dp[i][j], dp[i - 1][j] * calc2(w - 2, -1));
      //addm(dp[i][j], calc2(w - 2, -1));
    }
    else {
      addm(dp[i][j], dp[i - 1][j - 1] * calc(j - 2));
      //addm(dp[i][j], calc(j - 2));
      addm(dp[i][j], dp[i - 1][j + 1] * calc(j - 1));
      //addm(dp[i][j], calc(j - 1));
      addm(dp[i][j], dp[i - 1][j] * calc2(j - 2, j - 1));
      //addm(dp[i][j], calc2(j-2, j-1));
    }
  }
  cout << dp[h][k] << endl;
}


Compiler output:
a.cc: In function 'long long int calc(long long int)':
a.cc:147:15: error: no matching function for call to 'max(long long int, long long unsigned int)'
  147 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:147:15: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
  147 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:4:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:147:15: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
  147 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^
a.cc: In function 'long long int calc2(long long int, long long int)':
a.cc:167:15: error: no matching function for call to 'max(long long int, long long unsigned int)'
  167 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:167:15: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
  167 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:167:15: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
  167 |     rep(j, max(0LL, v.size() - 1LL)) {
      |            ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:52:34: note: in definition of macro 'rep'
   52 | #define rep(i,n) for (int i=0;i<(n);i++)
      |                                  ^