Submission #968277

#	Time	Username	Problem	Language	Result	Execution time	Memory
968277		Darren0724	Line Town (CCO23_day1problem3)	C++17	6 / 25	39 ms	12768 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(),x.end()
#define ll long long 
#define LCBorz ios_base::sync_with_stdio(false);cin.tie(0);
const int N=1000005;
const int mod=1e6+3;
const ll INF=1e18;
int32_t main(){
    LCBorz;
    int n;cin>>n;
    vector<ll> v(n+2),pre(n+2),suf(n+2);
    for(int i=1;i<=n;i++){
        cin>>v[i];
        assert(abs(v[i])<=1);
    }
    ll cnt=0;
    vector<int> st;
    int lz=0,zero=0,id=0;
    for(int i=1;i<=n;i++){
        if(v[i]==0){
            lz^=1;
            zero++;
        }
        else {
            id++;
            cnt+=zero;
            if((v[i]==1)^lz){
                if(st.size()&&(st.back()+id)%2==1){
                    cnt+=(id-st.back());
                    st.pop_back();
                } 
                else{
                    st.push_back(id);
                }
            }
        }
        if(st.size()==0){
            pre[i]=cnt;
        }
        else{
            pre[i]=INF;
        }
    }
    st.clear();
    cnt=0;
    lz=0;
    zero=0;
    id=0;
    for(int i=n;i>=1;i--){
        if(v[i]==0){
            lz^=1;
            zero++;
        }
        else {
            id++;
            cnt+=zero;
            if((v[i]==-1)^lz){
                if(st.size()&&(st.back()+id)%2==1){
                    cnt+=(id-st.back());
                    st.pop_back();
                } 
                else{
                    st.push_back(id);
                }
            }
        }
        if(st.size()==0){
            suf[i]=cnt;
        }
        else{
            suf[i]=INF;
        }
    }
    ll ans=INF;
    for(int i=0;i<=n;i++){
        ans=min(ans,pre[i]+suf[i+1]);
        //cout<<pre[i]<<' '<<suf[i+1]<<endl;
    }
    if(ans==INF){
        cout<<-1<<endl;
    }
    else{
        cout<<ans<<endl;
    }
    
    return 0;
}
/*
20
1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 -1 1 -1 -1 1
4
*/

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 0 / 3
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 3
• Subtask 7: 0 / 2
• Subtask 8: 0 / 3