CSES 1746 / DP

/***
 created: 2022-08-09-21.49.04
***/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename U> using ordered_set=tree<U, null_type,less<U>,rb_tree_tag,tree_order_statistics_node_update>;
#define ll long long
#define test int tt; cin>>tt; for(int cs=1;cs<=tt;cs++)
#define get_lost_idiot return 0
#define nl '\n'


ll dp[100005][105];
ll a[100005],n,m,mod=1e9+7;

ll solve(ll in,ll val)
{
    if(val<1 || val>m) return 0;

    if(a[in] && a[in]!=val) return 0;

    if(dp[in][val]!=-1) return dp[in][val];

    if(in==n) return 1;

    ll ans=((solve(in+1,val+1)%mod + solve(in+1,val-1)%mod)%mod+ solve(in+1,val)%mod)%mod;

    return dp[in][val]=ans;
}


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin>>n>>m;

    for(ll i=1; i<=n; i++)
    {
        cin>>a[i];
    }

    memset(dp,-1,sizeof dp);

    ll ans=0;

    for(ll i=1;i<=m;i++)
    {
        ans+=solve(1,i);
        ans%=mod;
    }

    cout<<ans<<nl;

    get_lost_idiot;
}