#include <bits/stdc++.h> #define all(aa) aa.begin(), aa.end() #define pb push_back #define endl ("\n") typedef long long ll; using namespace std; const int maxn = 2005, maxm = 2005; int n, m, target; bool vis[maxn][maxm]; vector<int> v[maxn]; ll d[maxn][maxm], sped; queue<array<ll, 3>> q; void pushq(ll u, ll s, ll dst){ if(u - s >= 0) q.push({u - s, s, dst+1}); if(u + s < n) q.push({u+s, s, dst+1}); } int main(){ cin >> n >> m; for(int i = 0; i < m; i++){ int b, p; cin >> b >> p; if(i == 0) sped = p; if(i != 1) v[b].pb(p); else target = b; } for(int i = 0; i < n; i++){ sort(all(v[i])); v[i].resize(unique(all(v[i])) - v[i].begin()); } pushq(0, sped, 0); while(!q.empty()){ auto [u, s, dst] = q.front(); q.pop(); if(u == target) cout << dst << endl, exit(0); if(vis[u][s]) continue; vis[u][s] = 1; d[u][s] = dst; for(int sp : v[u]) pushq(u, sp, dst); if(u - s >= 0) q.push({u - s, s, dst+1}); if(u + s < n) q.push({u+s, s, dst+1}); } cout << -1 << endl; }

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:36:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   36 |   auto [u, s, dst] = q.front(); q.pop();
      |        ^