dp小专题

Atcoder_ABC230F

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

typedef long long ll;
const int maxn=2e5+10;

const ll mod=998244353;

ll dp[maxn],pre[maxn];
map<ll,int>mp;
ll a[maxn];

int main(){
    #ifdef lmj_debug
        freopen("1.in","r",stdin);
    #endif
    int n;
    cin>>n;
    for (int i=1;i<=n;i++) scanf("%lld",&a[i]);
    for (int i=1;i<=n;i++) pre[i]=pre[i-1]+a[i];
    dp[1]=1;
    for (int i=1;i<n;i++){
        dp[i+1]=dp[i]*2-dp[mp[pre[i]]];
        dp[i+1]=(dp[i+1]+mod)%mod;

        mp[pre[i]]=i;
    }

    cout<<dp[n]<<endl;
    return 0;
}