Blocks

input/code.cpp: In function 'void solve()':
input/code.cpp:24:48: error: expected initializer before '>>' token
   24 |         for (int i = 0; i < n; i++) int c, cin >> c, f[c]++;
      |                                                ^~
input/code.cpp:24:41: warning: unused variable 'c' [-Wunused-variable]
   24 |         for (int i = 0; i < n; i++) int c, cin >> c, f[c]++;
      |                                         ^
input/code.cpp: In function 'int main()':
input/code.cpp:67:20: error: expected initializer before '>>' token
   67 |         int t, cin >> t;
      |                    ^~

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

void imp() { cout << "NO\n"; }
void evencase(int n, int k, vector<int> &f) {
	for (int c = 1; c <= k; c++) if (f[c] % 2 == 1) return imp();
	cout << "YES\n";

	vector<int> res;
	for (int c = 1; c <= k; c++) for (int i = 0; i < f[c] / 2; i++) res.push_back(c);

	for (int e : res) cout << e << " ";
	reverse(res.begin(), res.end());
	for (int e : res) cout << e << " ";
	cout << "\n";
}

void solve() {
	int n, k;
	cin >> n >> k;

	vector<int> f(k + 1);
	for (int i = 0; i < n; i++) int c, cin >> c, f[c]++;
	if (n % 2 == 0) return evencase(n, k, f);

	int m = n / 2, oddcnt = 0, onecnt = 0;
	for (int c = 1; c <= k; c++) oddcnt += f[c] & 1, onecnt += (f[c] == 1);

	int comps = oddcnt / 2;
	if (onecnt > 1 || comps > m / 3) return imp();

	cout << "YES\n";
	vector<int> resa(m), resb(m);
	for (int i = 0; i < comps; i++) {
		resb[i] = resa[3 * comps - (i + 1)] = resb[3 * comps - 2 * (i + 1)] = (i + 1) * (comps % 2 + 1);
		resa[i] = resa[i + comps] = resb[2 * i + comps + 1] = oddcnt - resb[i];
	}

	vector<int> oddies;
	for (int c = 1; c <= k; c++) if (f[c] & 1) {
		oddies.push_back(c);
		if (f[c] == 1) swap(oddies.back(), oddies.front());
	}

	for (int &e : resa) if (e) f[oddies[e]]--, e = oddies[e];
	for (int &e : resb) if (e) f[oddies[e]]--, e = oddies[e];
	f[oddies[0]]--;

	stack<int> stck;
	for (int c = 1; c <= k; c++) for (int i = 0; i < f[c]; i += 2) stck.push(c);
	for (int i = 0; i < m; i++) if (resa[i] == 0) {
		resa[i] = resb[i] = stck.top();
		stck.pop();
	}

	reverse(resb.begin(), resb.end());
	for (int e : resb) cout << e << " ";
	cout << oddies[0];
	for (int e : resa) cout << " " << e;
	cout << "\n";
}

signed main() {
	cin.tie(0)->sync_with_stdio(0);

	int t, cin >> t;
	while (t--) solve();

	return 0;
}