#include <bits/stdc++.h>
using namespace std
int cnt[100005], l[100005], r[100005], n, m;
vector<pair<int, int>> adj[100005 * 2];
vector<int> path;
int vis[100005 * 2], timer;
bool dfs(int u, int p) {
if (u == p) return 1;
if (vis[u] == timer) return 0;
vis[u] = timer;
for (auto e : adj[u]) {
int v, i; tie(v, i) = e;
path.push_back(i);
if (dfs(v, p)) return 1;
path.pop_back();
}
return 0;
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m;
for (int i = 1; i <= m; i++) cin >> l[i] >> r[i];
int x = *min_element(l + 1, l + m + 1);
for (int i = 1; i <= m; i++) {
l[i] -= x; r[i] -= x;
if (r[i] < 0) r[i] += n;
}
for (int i = 1; i <= m; i++)
if (l[i] <= r[i]) {
cnt[l[i]]++; cnt[r[i] + 1]--;
adj[l[i]].emplace_back(r[i] + 1, i);
adj[l[i] + n].emplace_back(r[i] + 1 + n, i);
} else {
cnt[0]++; cnt[l[i]]++; cnt[r[i] + 1]--;
adj[l[i]].emplace_back(r[i] + 1 + n, i);
adj[l[i] + n].emplace_back(2 * n, i);
}
for (int i = 0; i < n; i++) {
cnt[i + 1] += cnt[i];
if (cnt[i] < 2) return cout << "impossible", 0;
if (cnt[i] > 2) {
adj[i + 1].emplace_back(i, 0);
adj[i + 1 + n].emplace_back(i + n, 0);
}
}
for (int i = 0; i < n; i++) {
timer++;
if (dfs(i, i + n)) {
memset(cnt, 0, sizeof cnt);
for (int i : path) cnt[i] = 1;
for (int i = 1; i <= m; i++) cout << cnt[i];
return 0;
}
}
cout << "impossible";
}
Compilation message
alternating.cpp:2:20: error: expected ';' before 'int'
2 | using namespace std
| ^
| ;
3 |
4 | int cnt[100005], l[100005], r[100005], n, m;
| ~~~
