// author : anhtun_hi , nqg
// 25-26.12.2024
#include <bits/stdc++.h>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define reset(h, v)    memset(h, v, sizeof h)
#define Forv(i, a)     for(auto& i : a)
#define For(i, a, b)   for(int i = a; i <= b; ++i)
#define Ford(i, a, b)  for(int i = a; i >= b; --i)
#define c_bit(i)     __builtin_popcountll(i)
#define Bit(mask, i)    ((mask >> i) & 1LL)
#define onbit(mask, i)  ((mask) bitor (1LL << i))
#define offbit(mask, i) ((mask) &~ (1LL << i))
#define Log2(x) (63 - __builtin_clzll(x))
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
using namespace std;
using ll = long long;
using ii = pair<ll, ll>;
using db = long double;
using ull = unsigned long long;
namespace std {
    template <typename T, int D>
    struct _vector : public vector <_vector <T, D - 1>> {
        static_assert(D >= 1, "Dimension must be positive!");
        template <typename... Args>
        _vector(int n = 0, Args... args) : vector <_vector <T, D - 1>> (n, _vector <T, D - 1> (args...)) {}
    };
    template <typename T> struct _vector <T, 1> : public vector <T> {
        _vector(int n = 0, const T& val = T()) : vector <T> (n, val) {}
    };
    template <class A, class B> bool minimize(A &a, B b){return a > b ? a = b, true : false;}
    template <class A, class B> bool maximize(A &a, B b){return a < b ? a = b, true : false;}
}
const int dx[] = {0, 0, +1, -1}, dy[] = {-1, +1, 0, 0}, LOG = 20, base = 311, inf = 1e9 + 5;
const int MAXN = 1e6 + 5;
const  ll  mod = 1e6 + 3;
const  ll   oo = 1e18;
//#define int long long
int n, k, a[MAXN];
namespace Mod{
    inline void add(int &x, const int &y) { if((x += y) >= mod) x -= mod; }
    inline void sub(int &x, const int &y) { if((x -= y) < 0) x += mod; }
    inline void Mul(int &x, const int &y) { x = 1LL * x * y % mod; }
    inline int mul(const int &x, const int &y) { return 1LL * x * y % mod; }
    inline int sum(const int &x, const int &y) { int res = x + y; if(res >= mod) res -= mod; return res; }
    inline int diff(const int &x, const int &y) { int res = x - y; if(res < 0) res += mod; return res; }
} using namespace Mod;
namespace sub3{
    int dp[1005][(1 << 10) + 5];
    int solve(int i, int mask)
    {
        if (i > n) return 1;
        if (~dp[i][mask]) return dp[i][mask];
        int res = 0;
        For(j, 0, 1){
            int nmask = mask;
            nmask >>= 1;
            nmask |= j * (1 << (k - 1));
            if (a[i] == c_bit(nmask)) (res += solve(i + 1, nmask)) %= mod;
        }
        return dp[i][mask] = res;
    }
    void Solve(){
        memset(dp, -1, sizeof dp);
        int res = 0;
        For(mask, 0, (1 << k) - 1){
            if (c_bit(mask) == a[k])
            (res += solve(k + 1, mask)) %= mod;
        }
        cout << res << '\n';
    }
}
long long Pow(long long a, long long n) {
    long long res = 1;
    while (n > 0) {
        if (n & 1) res = (res * a) % mod;
        a = (a * a) % mod, n >>= 1;
    }
    return res;
}
struct Ckn {
    long long fac[1000000+100], ifac[1000000+100];
    void init(long long n) {
        fac[0] = 1; For(i, 1, n) fac[i] = (1ll * i * fac[i - 1]) % mod;
        ifac[n - 1] = Pow(fac[n - 1], mod - 2);
        Ford(i, n-2, 0) ifac[i] = (1ll * (i + 1) * ifac[i + 1]) % mod;
    }
    long long ckn(long long r, long long n){
        if (n < r) return 0;
        return fac[n] * ifac[r] % mod * ifac[n - r] % mod;
    }
    //             (k, n) = 0 if k > n
    //             (k, n) = n * nf[k] * (k - 1, n - 1)
    //       sigma (i, n) = 2 ^ n              :i = 0 -> n
    //       sigma (k, i) = (k + 1, n + 1)     :i = 0 -> n
    //  sigma (i, n + i)  = (m, n + m + 1)     :i = 0 -> m
    // sigma {(i, n) ^ 2} = (n, 2n)            :i = 0 -> n
    // sigma {k * (k, n)} = n * 2 ^ (n - 1)    :i = 1 -> n
    // x[1] + x[2] + .. + x[n]  = m (x[i] >= 0) => (n - 1, m + n - 1)
    // x[1] + x[2] + .. + x[n] <= m (x[i] >= 0) => (n, m + n)
    // cell(u, v) -> cell(x, y) => (x - u, x + y - u - v)
} C;
namespace subfull{
    vector<int> g[MAXN];
    int f[MAXN], c[MAXN];
    struct disjoint_set{
        int par[MAXN];
        void init() {
            For(i, 1, n) par[i] = -1;
        }
        int find(int u) {
            return (par[u] < 0) ? u : (par[u] = find(par[u]));
        }
        bool merge(int u, int v) {
            u = find(u), v = find(v);
            if (u == v) return false;
            if (par[u] > par[v]) swap(u, v);
            par[u] += par[v], par[v] = u;
            return true;
        }
    } dsu;
    void Solve(){
        C.init(1e6);
        dsu.init();
        For(i, 1, n - k + 1) f[i] = a[i + k - 1];
        For(i, 1, n) c[i] = -1;
        For(i, 1, n - k){
            if (abs(f[i] - f[i + 1]) > 1) {cout << 0; return;}
            if (f[i] == f[i + 1]){
                dsu.merge(i, i + k);
            }
        }
        For(i, 1, n - k){
            if (f[i] > f[i + 1]){
                int u = dsu.find(i);
                int v = dsu.find(i + k);
                g[u].push_back(v);
                if (c[u] == 0) {
                    cout << 0; return;
                }
                if (c[v] == 1) {
                    cout << 0; return;
                }
                c[u] = 1;
                c[v] = 0;
            } else if (f[i] < f[i + 1]){
                int u = dsu.find(i);
                int v = dsu.find(i + k);
                g[v].push_back(u);
                if (c[u] == 1) {
                    cout << 0; return;
                }
                if (c[v] == 0) {
                    cout << 0; return;
                }
                c[u] = 0;
                c[v] = 1;
            }
        }
        int ans = 1, cnt = 0;
        For(i, 1, k){
            int u = dsu.find(i);
            if (c[u] == -1) ++cnt;
            f[1] -= (c[u] == 1);
        }
        cout << C.ckn(f[1], cnt) << '\n';
    }
}
void Solve() {
    cin >> n >> k;
    For(i, k, n) cin >> a[i];
//    sub3::Solve();
    subfull::Solve();
}
signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    if(fopen("a.inp", "r")) {
        freopen("a.inp", "r", stdin);
        freopen("a.out", "w", stdout);
    }
    int t = 1;
//    cin >> t;
    while(t --) Solve();
    return 0;
}
컴파일 시 표준 에러 (stderr) 메시지
Main.cpp: In function 'int main()':
Main.cpp:200:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  200 |         freopen("a.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Main.cpp:201:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  201 |         freopen("a.out", "w", stdout);
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