Submission #968177

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
968177	2024-04-23 08:20:11	LittleOrange	Line Town (CCO23_day1problem3)	C++17	0 / 25	1 ms	348 KiB

Main

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#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<array<ll,3>> dp(n+1,{big,big,big});
    dp[0] = {0,0,0};
    for(ll i = 0;i<n;i++){
        if (a[i] == -1){
            dp[i+1][0] = min(dp[i+1][0],dp[i][0]);
            if(i&&a[i-1]==-1) dp[i+1][2] = min(dp[i+1][2],dp[i-1][2]+1);
        }else if (a[i] == 1){
            dp[i+1][2] = min(dp[i+1][2],dp[i][2]);
            if(i&&a[i-1]==1) dp[i+1][0] = min(dp[i+1][0],dp[i-1][0]+1);
        }else{
            dp[i+1][1] = min(dp[i+1][1],dp[i][1]);
        }
        dp[i+1][1] = min(dp[i+1][1],dp[i+1][0]);
        dp[i+1][2] = min(dp[i+1][2],dp[i+1][1]);
    }
    ll ans = dp[n][2];
    cout << (ans>=big?-1:ans) << "\n";
}
 
 
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• Subtask 2: 0 / 3
• Subtask 3: 0 / 3
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• Subtask 6: 0 / 3
• Subtask 7: 0 / 2
• Subtask 8: 0 / 3