Codeforces-SolutionsA/Codes/1980 D - GCD-sequence/1980D.cpp

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2024-06-07 02:15:29 +08:00
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
bool good(vector<int>v, int del)
{
v.erase(v.begin()+del);
int last=gcd(v[0],v[1]);
for(int i=1; i<v.size()-1; ++i)
{
int cur=gcd(v[i],v[i+1]);
if(cur<last)
{
del=i;
return false;
}
last=cur;
}
return true;
}
void solve()
{
int n;
cin>>n;
vector<int>v(n);
for(auto &i:v) cin>>i;
int del=-1;
int last=gcd(v[0],v[1]);
for(int i=1; i<n-1; ++i)
{
int cur=gcd(v[i],v[i+1]);
if(cur<last)
{
del=i;
break;
}
last=cur;
}
if(del==-1)
{
cout<<"YES\n";
return;
}
if(good(v,del-1) || good(v,del) || good(v,del+1)) cout<<"YES\n";
else cout<<"NO\n";
}
signed main()
{
ios_base::sync_with_stdio(false), cin.tie(nullptr);
int TCS = 1;
cin >> TCS;
for (int TC = 1; TC <= TCS; ++TC)
{
// cout<<"Case "<<TC<<": ";
solve();
}
}