#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int p[100002];
bool dp[100002][3];
vector<int> moves;
// void solve(array<int, 3> seg) {
// if (seg[2] == seg[0]) return;
// if ((seg[2] - seg[0]) & 1) {
// impossible = true;
// return;
// }
// moves.push_back(seg[1]);
// if (seg[2] - seg[1] == seg[1] - seg[0])
// solve({seg[0] + 1, seg[1], seg[2] - 1});
// else if (seg[2] - seg[1] == 1)
// solve({seg[0], (seg[0] + seg[2] - 2) / 2, seg[2] - 2});
// else if (seg[1] - seg[0] == 1)
// solve({seg[0] + 2, (seg[0] + seg[2] + 2) / 2, seg[2]});
// else
// solve({seg[0] + 1, seg[1], seg[2] - 1});
// }
int main() {
cin.tie(0)->sync_with_stdio(0);
int t;
cin >> t;
while (t--) {
moves.clear();
int n, m;
cin >> n >> m;
for (int i = 1; i <= m; i++) cin >> p[i];
p[0] = 0, p[m + 1] = n + 1;
memset(dp, 0, sizeof dp);
dp[0][0] = true;
for (int i = 1; i <= m + 1; i++) {
if (p[i] - p[i - 1] == 1) dp[i][0] |= dp[i - 1][0];
else dp[i][0] |= dp[i - 1][1 + (p[i] - p[i - 1]) % 2];
if ((p[i] - p[i - 1]) % 2 == 0) {
dp[i][1] |= dp[i - 1][0];
if (p[i] - p[i - 1] > 2) {
dp[i][1] |= dp[i - 1][2];
dp[i][2] |= dp[i - 1][1];
}
} else if (p[i] - p[i - 1] > 1) {
dp[i][2] |= dp[i - 1][0];
dp[i][1] |= dp[i - 1][1];
if (p[i] - p[i - 1] > 3)
dp[i][2] |= dp[i - 1][2];
}
}
// for (int j = 0; j < 3; j++) {
// for (int i = 0; i <= m + 1; i++) {
// cout << dp[i][j] << ' ';
// }
// cout << '\n';
// }
// for (int j = 1; j <= m; j++) cout << p[j] << ' ';
// cout << '\n';
if (dp[m + 1][0]) {
cout << "0\n\n";
} else cout << "-1\n";
}
return 0;
}
/*
Hack case:
1
11 3
4 8 10
Answer:
4
4 4 4 10
Hack case:
1
18 8
2 6 9 11 15 16 17 18
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
588 KB |
Output is partially correct |
2 |
Correct |
7 ms |
588 KB |
Output is partially correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
588 KB |
Output is partially correct |
2 |
Correct |
7 ms |
588 KB |
Output is partially correct |
3 |
Correct |
29 ms |
592 KB |
Output is partially correct |
4 |
Correct |
29 ms |
676 KB |
Output is partially correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
9 ms |
588 KB |
Output is partially correct |
2 |
Correct |
4 ms |
588 KB |
Output is partially correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
588 KB |
Output is partially correct |
2 |
Correct |
7 ms |
588 KB |
Output is partially correct |
3 |
Correct |
29 ms |
592 KB |
Output is partially correct |
4 |
Correct |
29 ms |
676 KB |
Output is partially correct |
5 |
Correct |
2 ms |
588 KB |
Output is partially correct |
6 |
Correct |
2 ms |
588 KB |
Output is partially correct |
7 |
Correct |
2 ms |
588 KB |
Output is partially correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
588 KB |
Output is partially correct |
2 |
Correct |
7 ms |
588 KB |
Output is partially correct |
3 |
Correct |
29 ms |
592 KB |
Output is partially correct |
4 |
Correct |
29 ms |
676 KB |
Output is partially correct |
5 |
Correct |
2 ms |
588 KB |
Output is partially correct |
6 |
Correct |
2 ms |
588 KB |
Output is partially correct |
7 |
Correct |
2 ms |
588 KB |
Output is partially correct |
8 |
Correct |
7 ms |
716 KB |
Output is partially correct |
9 |
Correct |
8 ms |
844 KB |
Output is partially correct |
10 |
Correct |
7 ms |
836 KB |
Output is partially correct |
11 |
Correct |
7 ms |
844 KB |
Output is partially correct |