#include <bits/stdc++.h> using namespace std; #define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0) #define fi first #define se second #define debug(x) cerr << " - " << #x << ": " << x << endl; #define debugs(x, y) cerr << " - " << #x << ": " << x << " " << #y << ": " << y << endl; #define debugii(x) cerr << " - " << #x << ": " << x.fi<<","<<x.se << endl; #define sep() cerr << "--------------------" << endl; #define all(x) (x).begin(),(x).end() #define sz(x) (ll)x.size() #define ll long long #define int ll #define ii pair<int,int> #define v vector<int> #define vii vector<ii> #define vv vector<vector<ii> > #define mp make_pair #define INF 100000000000 #define pb push_back #define EPS 1e-9 const int MOD = 1000000007; // 998244353 int B[300005],P[300005]; int dist[300005]; vv vec; main(){ boost; int N,M; cin>>N>>M; vec.resize(N); for (int i = 0; i < M; ++i){ cin>>B[i]>>P[i]; for (int j = B[i],z=0; j < N; j+=P[i],z++) { //debug(j); vec[B[i]].pb({j,z}); //vec[j].pb({B[i],z}); } for (int j = B[i]-P[i],z=1; j >=0 ; j-=P[i],z++) { //debug(j); vec[B[i]].pb({j,z}); //vec[j].pb({B[i],z}); } //sep() } for (int i = 0; i < N; ++i) dist[i]=INF; dist[B[0]]=0; priority_queue<ii,vii,greater<ii> > pq; pq.push({0,B[0]}); while(!pq.empty()){ ii front=pq.top(); //debugii(front); pq.pop(); if(dist[front.se]<front.fi)continue; for(auto it:vec[front.se]){ if(dist[it.fi]>dist[front.se]+it.se){ dist[it.fi]=dist[front.se]+it.se; pq.push({dist[it.fi],it.fi}); } } } if(dist[B[1]]==INF)cout<<-1; else cout<<dist[B[1]]; cout<<"\n"; return 0; } //long long //array bounds //special cases //binary search

skyscraper.cpp:26:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^