#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;
optional<int> find_edge_between(vector<int> s, int v) {
if (!are_connected(s, {v})) return nullopt;
vector<int> current = s;
while (current.size() > 1) {
int hs = current.size() / 2;
vector<int> h1(begin(current), begin(current) + hs), h2(begin(current) + hs, end(current));
if (are_connected(h1, {v})) current = h1;
else current = h2;
}
return current[0];
}
optional<pair<int, int>> find_edge_between(vector<int> s1, vector<int> s2) {
if (!are_connected(s1, s2)) return nullopt;
vector<int> current = s1;
while (current.size() > 1) {
int hs = current.size() / 2;
vector<int> h1(begin(current), begin(current) + hs), h2(begin(current) + hs, end(current));
if (are_connected(h1, s2)) current = h1;
else current = h2;
}
return make_pair(current[0], find_edge_between(s2, current[0]).value());
}
std::vector<int> longest_trip(int N, int D) {
deque<int> p1{0}, p2;
for (int i = 1; i < N; ++i) {
if (are_connected({p1.back()}, {i})) {
if (are_connected({i}, {p2.front()})) {
p1.push_back(i);
p1.insert(end(p1), begin(p2), end(p2));
p2.clear();
} else {
p1.push_back(i);
}
} else if (!p2.empty()) {
p2.push_front(i);
} else {
p2.push_back(i);
}
}
/*
cout << "p1: ";
for (int v : p1) cout << v;
cout << endl;
cout << "p2: ";
for (int v : p2) cout << v;
cout << endl;
*/
vector<int> fp1(p1.begin(), p1.end()), fp2(p2.begin(), p2.end());
if (fp1.size() == N) return fp1;
if (fp2.size() > 1 && !are_connected({fp2.front()}, {fp2.back()})) {
vector<int> ans = fp1;
reverse(begin(fp2), end(fp2));
ans.insert(end(ans), begin(fp2), end(fp2));
return ans;
}
if (fp1.size() > 1 && !are_connected({fp1.front()}, {fp1.back()})) {
vector<int> ans = fp2;
reverse(begin(fp2), end(fp2));
ans.insert(end(ans), begin(fp1), end(fp1));
return ans;
}
auto bridge = find_edge_between(fp1, fp2);
if (!bridge) {
return fp1.size() > fp2.size() ? fp1 : fp2;
}
auto left_end_iter = find(begin(fp2), end(fp2), bridge->second);
rotate(begin(fp2), left_end_iter, end(fp2));
auto right_end_iter = find(begin(fp1), end(fp1), bridge->first);
rotate(begin(fp1), right_end_iter, end(fp1));
vector<int> ans = fp2;
reverse(begin(ans), end(ans));
ans.insert(end(ans), begin(fp1), end(fp1));
return ans;
}
Compilation message
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:56:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
56 | if (fp1.size() == N) return fp1;
| ~~~~~~~~~~~^~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
4 ms |
436 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
8 ms |
344 KB |
Output is correct |
2 |
Correct |
9 ms |
344 KB |
Output is correct |
3 |
Correct |
8 ms |
344 KB |
Output is correct |
4 |
Incorrect |
2 ms |
344 KB |
invalid array |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
8 ms |
344 KB |
Output is correct |
2 |
Correct |
9 ms |
344 KB |
Output is correct |
3 |
Correct |
9 ms |
344 KB |
Output is correct |
4 |
Incorrect |
1 ms |
344 KB |
invalid array |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
8 ms |
344 KB |
Output is correct |
2 |
Correct |
9 ms |
344 KB |
Output is correct |
3 |
Correct |
9 ms |
344 KB |
Output is correct |
4 |
Incorrect |
1 ms |
432 KB |
invalid array |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
8 ms |
344 KB |
Output is correct |
2 |
Correct |
9 ms |
344 KB |
Output is correct |
3 |
Correct |
6 ms |
344 KB |
Output is correct |
4 |
Incorrect |
1 ms |
344 KB |
invalid array |
5 |
Halted |
0 ms |
0 KB |
- |