说谎与诚实的人

https://codeforces.com/problemset/problem/2061/C

#include<bits/stdc++.h>
using namespace std;

#define endl '\n'
using ll = long long;
using pii = pair<int, int>;
const double PI = acos(-1);
const int N =2e5+10;
const int mod = 998244353;
int dp[N][2];
int a[N];
void solve(){
	int n;cin>>n;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	for(int i=0;i<=n;i++)
		dp[i][0]=dp[i][1]=0;
	if(a[1]==0){
		dp[1][0]=dp[1][1]=1;
	}
	else{
		dp[1][0]=1;
	}
	for(int i=2;i<=n;i++){
		dp[i][0]=dp[i-1][1]%mod;
		if(a[i-2]+1==a[i]){
			dp[i][1]=(dp[i][1]+dp[i-1][0])%mod;
		}
		if(a[i-1]==a[i]){
			dp[i][1]=(dp[i][1]+dp[i-1][1])%mod;
		}
	}
	cout<<(dp[n][0]+dp[n][1])%mod<<endl;
}
int main() {
	
	ios::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	
	int T = 1;
	cin>>T;
	while (T--) {
		solve();
	}
	
	return 0;
}