#include <bits/stdc++.h> using namespace std; const int mx = 1e5+5; int n, m; int ans; struct Edge { int ty; int fr, to; } e[mx]; int main() { cin.tie(0);ios::sync_with_stdio(0); cin >> n >> m; for (int i=0;i<m;i++) { cin >> e[i].fr >> e[i].to; if (e[i].fr == e[i].to) { e[i].ty = 0; } else if (e[i].fr < e[i].to) { e[i].ty = 1; } else { e[i].ty = 2; } } bool fl = 0; for (int i=0;i<(1<<m);i++) { set<int> s[2]; for (int j=0;j<m;j++) { int tp = (i&(1<<j)?1:0); if (e[j].ty == 0) { s[tp].insert(e[j].fr); } else if (e[j].ty == 1) { for (int k=e[j].fr;k<=e[j].to;k++) { s[tp].insert(k); } } else { for (int k=e[j].fr;k<=n;k++) { s[tp].insert(k); } for (int k=1;k<=e[j].to;k++) { s[tp].insert(k); } } } if (s[0].size() == n and s[1].size() == n) { fl = 1; ans = i; break; } } if (fl) { for (int i=0;i<m;i++) { cout << ((1<<i)&ans?1:0); } cout << "\n"; } else { cout << "impossible\n"; } }

alternating.cpp: In function 'int main()':
alternating.cpp:47:19: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   47 |   if (s[0].size() == n and s[1].size() == n) {
      |       ~~~~~~~~~~~~^~~~
alternating.cpp:47:40: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   47 |   if (s[0].size() == n and s[1].size() == n) {
      |                            ~~~~~~~~~~~~^~~~