Gimme your money:D

HOÁN VỊ

include <bits/stdc++.h>

using namespace std; const int N=1e6; int a[N],b[N],n,k; int main() { iosbase::syncwith_stdio(false); cin.tie(NULL); cin>>n; for (int i=0;i<n;i++) b[i]=i+1; for (int i=0;i<n;i++) cin>>a[i]; sort(a,a+n); int sum=0; for (int i=0;i<n;i++) { if (a[i]==b[i]) sum++; } if (sum==n) cout<<"YES"; else cout<<"NO"; }