Submission #968254

#	Time	Username	Problem	Language	Result	Execution time	Memory
968254		LittleOrange	Line Town (CCO23_day1problem3)	C++17	0 / 25	0 ms	348 KiB

Main

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll big = 1e18;
int main(){
    ios::sync_with_stdio(0);cin.tie(0);
    ll n;
    cin >> n;
    vector<ll> a(n);
    for(ll &i : a) cin >> i;
    vector<ll> l(n,big),r(n,big);
    ll cur = 0;
    vector<ll> b = a;
    for(ll i = 0;i<n;i++){
        if (b[i]==1){
            if (i+1==n) break;
            if (b[i+1]==1){
                b[i] = -1;
                b[i+1] = -1;
                cur++;
            }else{
                if (i+2==n||b[i+2]!=-1) break;
                b[i] = -1;
                b[i+2] = 1;
            }
        }
        l[i] = cur;
    }
    b = a;
    reverse(b.begin(),b.end());
    cur = 0;
    for(ll i = 0;i<n;i++){
        if (b[i]==-1){
            if (i+1==n) break;
            if (b[i+1]==-1){
                b[i] = 1;
                b[i+1] = 1;
                cur++;
            }else{
                if (i+2==n||b[i+2]!=1) break;
                b[i] = 1;
                b[i+2] = -1;
            }
        }
        r[i] = cur;
    }
    ll ans = min(l.back(),r.back());
    for(ll i = 0;i<n-1;i++){
        ans = min(ans,l[i]+r[n-2-i]);
    }
    cout << (ans>=big?-1:ans) << "\n";
}

• Subtask 1: 0 / 3
• Subtask 2: 0 / 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