func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e3 + 10;   const int mod = 998244353;   int f[N][N], g[N][N];   int mn[N][N], indl[N], indr[N];   bool bz[N][N];   int a[1000001];   int n, m;   int main() {     scanf( %d %d , &n, &m);     for (int i = 1; i <= m; i++) scanf( %d , &a[i]);     int x = m;     m = 1;     for (int i = 2; i <= x; i++)       if (a[i] != a[m]) a[++m] = a[i];     for (int i = 1; i <= m; i++) {       if (!indl[a[i]]) indl[a[i]] = i;       indr[a[i]] = i;     }     if (m > 3 * n) {       printf( 0 n );       return 0;     }     for (int i = 1; i <= n; i++)       for (int j = indl[i]; j <= indr[i]; j++)         if (a[j] < i) {           printf( 0 n );           return 0;         }     for (int i = 1; i <= m; i++) {       mn[i][i] = a[i];       for (int j = i + 1; j <= m; j++) mn[i][j] = min(mn[i][j - 1], a[j]);     }     for (int i = 1; i <= m + 1; i++) f[i][i - 1] = g[i][i - 1] = 1;     for (int i = 1; i <= m; i++)       for (int l = 1; l + i - 1 <= m; l++) {         int r = i + l - 1;         int x = mn[l][r], idl = indl[x], idr = indr[x];         if (idl > r || idr < l) continue;         int v = 1;         int lll = idl;         while (lll != idr) {           int rrr = lll + 1;           while (a[rrr] != a[lll]) rrr++;           v = (long long)v * f[lll + 1][rrr - 1] % mod;           lll = rrr;         }         for (int mid = idr; mid <= r; mid++)           g[l][r] = (g[l][r] + (long long)f[l][idl - 1] * f[mid + 1][r] % mod *                                    v % mod * f[idr + 1][mid] % mod) %                     mod;         for (int ll = l; ll <= idl; ll++)           f[l][r] = (f[l][r] + (long long)g[ll][r] * f[l][ll - 1]) % mod;       }     printf( %d n , f[1][m]);     return 0;   }   