Submission #569671

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
int N;
int A[100001];
typedef long long ll;
int main(){
  cin>>N;
  for(int i=0;i<N;i++) cin >> A[i];
  ll lsum=A[0], rsum=A[N-1];
  int li=1,ri=N-2;
  ll res = 0;
  while( li <= ri ){
    ll lc = lsum*2LL + A[li] + 1LL;
    ll rc = rsum*2LL + A[ri] + 1LL;
    // cout << li << ": " << lc << ", " << ri << ": " << rc << endl;
    if( lc < rc ){
      lsum += A[li] + A[li+1] + 2LL;
      res += lc;
      li+=2;
    } else {      
      rsum+= A[ri] + A[ri-1] + 2LL;
      res += rc;
      ri-=2;
    }
  }
  cout << res << endl;
}

Submission Info

Judge Result