func_code_string: #include <bits/stdc++.h>   template <class T>   inline bool chmax(T& a, T b) {     if (a < b) {       a = b;       return 1;     }     return 0;   }   template <class T>   inline bool chmin(T& a, T b) {     if (a > b) {       a = b;       return 1;     }     return 0;   }   constexpr long long MAX = 5100000;   constexpr long long INF = 1LL << 60;   constexpr int inf = 1000000007;   constexpr long long mod = 998244353LL;   const long double PI = acos((long double)(-1));   using namespace std;   struct mint {     long long x;     mint(long long x = 0) : x((x % mod + mod) % mod) {}     mint& operator+=(const mint a) {       if ((x += a.x) >= mod) x -= mod;       return *this;     }     mint& operator-=(const mint a) {       if ((x += mod - a.x) >= mod) x -= mod;       return *this;     }     mint& operator*=(const mint a) {       (x *= a.x) %= mod;       return *this;     }     mint operator+(const mint a) const {       mint res(*this);       return res += a;     }     mint operator-(const mint a) const {       mint res(*this);       return res -= a;     }     mint operator*(const mint a) const {       mint res(*this);       return res *= a;     }     mint pow(long long t) const {       if (!t) return 1;       mint a = pow(t >> 1);       a *= a;       if (t & 1) a *= *this;       return a;     }     mint inv() const { return pow(mod - 2); }     mint& operator/=(const mint a) { return (*this) *= a.inv(); }     mint operator/(const mint a) const {       mint res(*this);       return res /= a;     }   };   mint dp[2][4001];   void init(int x) {     for (int i = 0; i <= 4000; i++) dp[x][i] = 0;   }   long long fac[MAX], finv[MAX], inv[MAX];   void COMinit() {     fac[0] = fac[1] = 1;     finv[0] = finv[1] = 1;     inv[1] = 1;     for (int i = 2; i < MAX; i++) {       fac[i] = fac[i - 1] * i % mod;       inv[i] = mod - inv[mod % i] * (mod / i) % mod;       finv[i] = finv[i - 1] * inv[i] % mod;     }   }   mint COM(int n, int k) {     if (n < k) return 0;     if (n < 0 || k < 0) return 0;     return mint(fac[n] * (finv[k] * finv[n - k] % mod) % mod);   }   int main() {     COMinit();     long long n, k;     scanf( %lld %lld , &n, &k);     vector<long long> h(n);     for (int i = 0; i < n; i++) scanf( %lld , &h[i]);     int cnt = 0;     for (int i = 0; i < n; i++) {       if (h[i] != h[(i + 1) % n]) {         cnt++;       }     }     mint res = 0;     vector<mint> k2(n + 1);     k2[0] = 1;     for (int i = 1; i <= n; i++) k2[i] = k2[i - 1] * (k - 2);     vector<mint> tw(n + 1);     tw[0] = 1;     for (int i = 1; i <= n; i++) tw[i] = tw[i - 1] * 2;     mint tinv = mint(2).inv();     for (int i = 0; i < cnt; i++) {       int r = cnt - i;       if (r & 1)         res += COM(cnt, i) * k2[i] * tw[r - 1];       else         res += COM(cnt, i) * k2[i] * (tw[r] - COM(r, r / 2)) * tinv;     }     res *= mint(k).pow(n - cnt);     cout << res.x <<   n ;     return 0;   }   