33 lines
479 B
C++
33 lines
479 B
C++
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#include<bits/stdc++.h>
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using namespace std;
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using ll = long long;
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void solve()
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{
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int n;
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cin>>n;
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vector<int>v(n+1);
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for(int i=1; i<=n; i++)
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{
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cin>>v[i];
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}
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int ans=0, diff;
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for(int i=1; i<=n; ++i)
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{
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diff=abs(v[i]-i);
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ans=__gcd(ans,diff);
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}
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cout<<ans<<endl;
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}
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int main()
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{
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ios_base::sync_with_stdio(false);
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cin.tie(nullptr);
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int TC = 1;
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cin >> TC;
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cin.ignore();
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while (TC--) solve();
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}
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