codeforces 1426D（思维）

#include<bits/stdc++.h>
#define x first
#define y second
#define PB push_back
#define mst(x,a) memset(x,a,sizeof(x))
#define all(a) begin(a),end(a)
#define rep(x,l,u) for(ll x=l;x<u;x++)
#define rrep(x,l,u) for(ll x=l;x>=u;x--)
#define sz(x) x.size()
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef pair<long,long> PLL;
typedef pair<char,char> PCC;
typedef long long ll;
const int N=2*1e5+10;
const int M=1e6+10;
const int INF=0x3f3f3f3f;
const int MOD=1e9+7;
/*注意边界
清空每个case的影响
注意数据范围
注意证明*/
int a[N];
void solve(){
    int n;cin>>n;
    rep(i,0,n) cin>>a[i];
    set<ll> s;
    s.insert(0);
    ll ans=0,res=0;
    rep(i,0,n){
        res+=a[i];
        if(s.count(res)){
            ans++;
            set<ll> ss;
            s=ss;
            s.insert(0);
            res=a[i];
        }
        s.insert(res);
    }
    cout<<ans<<endl;
}
int main(){
    //IOS;
    //int t;cin>>t;
    //while(t--)
        solve();
    return 0;
}