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MainSolution.cpp
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MainSolution.cpp
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#include <iostream>
#include <vector>
#include <unordered_set>
bool isChallengeSolvable(int n, const std::vector<int>& permutation) {
std::unordered_set<int> visited;
for (int i = 0; i < 2 * n; ++i) {
if (visited.find(i + 1) != visited.end()) {
continue; // Already visited
}
int current = permutation[i] - 1;
int length = 0;
while (visited.find(current + 1) == visited.end()) {
visited.insert(current + 1);
current = permutation[current] - 1;
++length;
}
if (length > n) {
return false;
}
}
return true;
}
int main() {
int n;
std::cin >> n;
std::vector<int> permutation(2 * n);
for (int i = 0; i < 2 * n; ++i) {
std::cin >> permutation[i];
}
if (isChallengeSolvable(n, permutation)) {
std::cout << "YES" << std::endl;
} else {
std::cout << "NO" << std::endl;
}
return 0;
}