#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int p[100002];
bool isolated[100002], impossible;
vector<int> moves;
void solve(array<int, 3> seg) {
if (seg[2] == seg[0]) return;
if ((seg[2] - seg[0]) % 2) {
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;
isolated[0] = isolated[m + 1] = false;
for (int i = 1; i <= m; i++) {
isolated[i] = p[i - 1] != p[i] - 1 && p[i + 1] != p[i] + 1;
}
impossible = false;
if ((n - m) & 1) impossible = true;
vector<array<int, 3>> segs;
for (int i = 1; i <= m + 1; i++) {
if (p[i - 1] != p[i] - 1 && !isolated[i] && !isolated[i - 1]) {
impossible = true;
break;
}
if (isolated[i]) {
if (isolated[i - 1]) {
if (segs.back()[2] == p[i] - 1)
isolated[i] = false;
else if (isolated[i + 1]) {
int needed = 1 + (p[i] - segs.back()[2]) % 2;
segs.push_back({segs.back()[2] + 1, p[i], min(p[i] + needed, p[i + 1] - 1)});
} else
segs.push_back({segs.back()[2] + 1, p[i], p[i + 1] - 1});
} else {
if (isolated[i + 1]) {
int needed = 1 + (p[i] - p[i - 1]) % 2;
segs.push_back({p[i - 1] + 1, p[i], min(p[i] + needed, p[i + 1] - 1)});
} else
segs.push_back({p[i - 1] + 1, p[i], p[i + 1] - 1});
}
}
}
for (auto i : segs) solve(i);
if (impossible) cout << "-1\n";
else {
cout << moves.size() << '\n';
while (moves.size()) {
cout << moves.back() << ' ';
moves.pop_back();
}
cout << '\n';
}
}
return 0;
}
Compilation message
grader.cpp: In function 'int main()':
grader.cpp:28:26: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wformat=]
28 | fprintf (fifo_out, "%d\n", ans.size ());
| ~^ ~~~~~~~~~~~
| | |
| int std::vector<int>::size_type {aka long unsigned int}
| %ld
grader.cpp:29:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
29 | for (int i=0; i<ans.size () && i < N; i++)
| ~^~~~~~~~~~~~
/tmp/ccRASI22.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccvlGu7n.o:hidden.cpp:(.text.startup+0x0): first defined here
/tmp/ccRASI22.o: In function `main':
grader.cpp:(.text.startup+0x41): undefined reference to `findSequence(int)'
collect2: error: ld returned 1 exit status
