简单容斥，不过感觉一毛一样的题做过，可能是在多校？？？
1 #define mm(a) memset(a,0,sizeof(a)); 2 #define max(x,y) (x)>(y)?(x):(y) 3 #define min(x,y) (x)<(y)?(x):(y) 4 #define Fopen freopen("1.in","r",stdin); freopen("m.out","w",stdout); 5 #define rep(i,a,b) for(ll i=(a);i<=(b);i++) 6 #define per(i,b,a) for(ll i=(b);i>=(a);i--) 7 #include<bits/stdc++.h> 8 typedef long long ll; 9 #define PII pair<ll,ll> 10 using namespace std; 11 const int INF=0x3f3f3f3f; 12 const int MAXN=(int)2e6+5; 13 const ll mod=998244353; 14 15 ll qpow(ll x,ll y) { 16 ll ans=1; 17 while(y) { 18 if(y&1)ans=(x*ans)%mod; 19 x=(x*x)%mod; 20 y>>=1; 21 } 22 return ans; 23 } 24 int main() { 25 ll a,b,c,d; 26 ll num1,num2,num3,num4,num5; 27 while(~scanf("%lld%lld%lld%lld",&a,&b,&c,&d)) { 28 ll a1=qpow(2,a),b1=qpow(2,b),c1=qpow(2,c),d1=qpow(2,d); 29 ll ans=a1; 30 ans+=a1*(c1-1)%mod; 31 ans+=a1*(b1-1)%mod; 32 ans+=b*a1%mod*(c1-1)%mod; 33 ans+=d*a1%mod*c1%mod; 34 printf("%lld ",ans%mod); 35 } 36 return 0; 37 }