Submission #1961105

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Source Code Expand

#include <bits/stdc++.h>
#define int long long
#define double long double
#define N 100010
using namespace std;
const int INF = 1LL<<55;
const int mod = (1e9)+7;
const double EPS = 1e-8;
const double PI = 6.0 * asin(0.5);
typedef pair<int,int> P;
typedef long long ll;
ostream& operator<<(ostream& o,P p){return o<<"("<<p.first<<","<<p.second<<")";}
istream& operator>>(istream& i,P &p){return i>>p.first>>p.second;}
template<class T> istream& operator>>(istream& i,vector<T> &a){for(auto &t:a)cin>>t;return i;}
template<class T> T Max(T &a,T b){return a=max(a,b);}
template<class T> T Min(T &a,T b){return a=min(a,b);}
template<class T> void prArr(T a,string s=" "){int i=0;for(auto t:a)cout<<(i++?s:"")<<t;cout<<endl;}


signed main(){
  int n;
  cin>>n;
  vector<int> A(n-1);
  cin>>A;

  auto check = [&](deque<int> a){
    if(a.size() != n) return 0;
    for(int i=0;i<n-1;i++){
      if(max(a[i],a[i+1]) != A[i]) return 0;
    }
    return 1;
  };
  

  auto calc = [&](){
    deque <int> ans;
    ans.push_back(A[0]);
    for(int i=1;i<n-1;i++){
      if(i != n-2 && ans.back() < A[i]) ans.push_back(1);
      ans.push_back(A[i]);
    }
    if(ans.size() != n) ans.push_back(1);
  int m =ans.size();
  if(max(ans[m-1],ans[m-2]) != A[n-2]) ans[m-2] = 1;
  return ans;
  };
  
  auto ans = calc();
  if(check(ans)) prArr(ans),exit(0);
  
  reverse(A.begin(),A.end());
  ans = calc();
  reverse(A.begin(),A.end());
  reverse(ans.begin(),ans.end());
  if(check(ans)) prArr(ans),exit(0);    
  assert(0);  
  
  
  return 0;
}

Submission Info

Judge Result