Submission #496944

#	Time	Username	Problem	Language	Result	Execution time	Memory
496944		abc864197532	DEL13 (info1cup18_del13)	C++17	100 / 100	19 ms	5936 KiB

del13

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define X first
#define Y second
#define pii pair<int,int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
	cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
	for (; l != r; ++l) 
		cout << *l << " \n"[l + 1 == r];
}
#ifdef Doludu
#define test(x...) abc("[" + string(#x) + "]", x);
#else
#define test(x...) void(0);
#endif
const int N = 1001;
 
int main () {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while (t--) {
		int n, m;
		cin >> n >> m;
		vector <int> a(m + 1, 0);
		vector <int> rem;
		for (int i = 1; i <= m; ++i) {
			cin >> a[i];
			rem.pb(a[i] - a[i - 1] - 1);
		}
		rem.pb(n - a[m]);
		vector <vector <int>> dp(m + 1, vector <int>(3, false));
		vector <vector <int>> rt(m + 1, vector <int>(3, -1));
		dp[0][0] = true;
		for (int i = 0; i < m; ++i) for (int f = 0; f <= 2; ++f) if (dp[i][f]) {
			int left = rem[i] - f;
			assert(left >= 0);
			if (left == 0) {
				dp[i + 1][0] = true;
				rt[i + 1][0] = f;
				continue;
			}
			if (left & 1) {
				// optimal 1
				if (rem[i + 1] >= 1)
					dp[i + 1][1] = true, rt[i + 1][1] = f;
			} else {
				if (f) {
					dp[i + 1][0] = true, rt[i + 1][0] = f;
				}
				if (rem[i + 1] >= 2)
					dp[i + 1][2] = true, rt[i + 1][2] = f;
			}
		}
		int now = -1;
		for (int i = 1; i <= 2; ++i) if (dp[m][i] && rem[m] >= i && (rem[m] - i) % 2 == 0)
			now = i;
		if (dp[m][0] && rem[m] == 0)
			now = 0;
		if (now != -1) {
			vector <int> move, fr;
			for (int i = m; ~i; --i) {
				for (int j = 0; j < now; ++j)
					move.pb(a[i]), rem[i - 1]--, rem[i]--;
				now = rt[i][now];
			}
			for (int i = 0; i <= m; ++i) {
				assert(rem[i] % 2 == 0);
				int mid;
				if (i < m)
					mid = a[i] + a[i + 1] >> 1;
				else mid = a[i] + n + 1 >> 1;
				for (int j = 0; j < rem[i] / 2; ++j) {
					fr.pb(mid);
				}
			}
			cout << fr.size() + move.size() << endl;
			for (int i : fr)
				cout << i << ' ';
			for (int i : move)
				cout << i << ' ';
			cout << endl;
		} else {
			cout << -1 << endl;
		}
	}
}

Compilation message (stderr)

del13.cpp: In function 'int main()':
del13.cpp:81:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   81 |      mid = a[i] + a[i + 1] >> 1;
del13.cpp:82:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   82 |     else mid = a[i] + n + 1 >> 1;

• Subtask 1: 15 / 15
• Subtask 2: 15 / 15
• Subtask 3: 15 / 15
• Subtask 4: 25 / 25
• Subtask 5: 30 / 30