abc205_b_permutation_check.cpp

// Permutation Check | https://atcoder.jp/contests/abc205/tasks/abc205_b
// Time: O(n); extra space: O(n).
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

void solve() {
    int n;
    std::cin>>n;
    std::vector<bool>seen(n);
    bool ok=true;
    while(n--) {
        int x;
        std::cin>>x;
        if(seen[x-1])ok=false;
        seen[x-1]=true;
    }
    std::cout<<(ok?"Yes":"No")<<'\n';
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    solve();
}