제출 #1264836

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1264836		hainam2k9	Olympic Bus (JOI20_ho_t4)	C++20	100 / 100	814 ms	6216 KiB

ho_t4

#include <bits/stdc++.h>
#define tt cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0)
#define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
#define ll long long
#define ull unsigned long long
#define i128 __int128
#define db long double
#define sz(a) ((int)(a).size())
#define pb emplace_back
#define pf emplace_front
#define pob pop_back
#define pof pop_front
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define ins emplace
#define mp make_pair
using namespace std;
const int MOD = 1e9+7, MAXN = 5e4+5;
const string NAME = "";
struct Edge{
    int from,to,weight,cost,pos;
}edge[MAXN];
int n,m,rs=2e9;
int dist1[205],distN[205],distrev1[205],distrevN[205];
Edge trace1[205],traceN[205];
bool inv[MAXN],vis[MAXN];
vector<Edge> adj[205],rev[205];
vector<int> v;
void dijkstra1(int u, int dist[], Edge trace[]){
    fill(dist+1,dist+n+1,1e9);
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    dist[u]=0, pq.ins(0,u);
    while(!pq.empty()){
        pair<int,int> top=pq.top();
        pq.pop();
        if(top.fi>dist[top.se]) continue;
        for(Edge& e : adj[top.se]){
            if(top.se!=e.from) continue;
            if(dist[e.to]>top.fi+e.weight) dist[e.to]=top.fi+e.weight, trace[e.to]=e, pq.ins(dist[e.to],e.to);
        }
    }
}
void dijkstrarev(int u, int dist[]){
    fill(dist+1,dist+n+1,1e9);
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    dist[u]=0, pq.ins(0,u);
    while(!pq.empty()){
        pair<int,int> top=pq.top();
        pq.pop();
        if(top.fi>dist[top.se]) continue;
        for(Edge& e : rev[top.se])
            if(dist[e.from]>top.fi+e.weight) dist[e.from]=top.fi+e.weight, pq.ins(dist[e.from],e.from);
    }
}
void dijkstra2(int u, int dist[]){
    fill(dist+1,dist+n+1,1e9);
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    dist[u]=0, pq.ins(0,u);
    while(!pq.empty()){
        pair<int,int> top=pq.top();
        pq.pop();
        if(top.fi>dist[top.se]) continue;
        for(Edge& e : adj[top.se]){
            if(!inv[e.pos]){
                if(top.se!=e.from) continue;
                if(dist[e.to]>top.fi+e.weight) dist[e.to]=top.fi+e.weight, pq.ins(dist[e.to],e.to);
            }else{
                if(top.se!=e.to) continue;
                if(dist[e.from]>top.fi+e.weight) dist[e.from]=top.fi+e.weight, pq.ins(dist[e.from],e.from);
            }
        }
    }
}
int main()
{
    tt;
    if(fopen((NAME + ".INP").c_str(), "r")) fo;
    cin >> n >> m;
    for(int i = 1; i<=m; ++i){
        cin >> edge[i].from >> edge[i].to >> edge[i].weight >> edge[i].cost, edge[i].pos=i;
        adj[edge[i].from].pb(edge[i]), adj[edge[i].to].pb(edge[i]);
        rev[edge[i].to].pb(edge[i]);
    }
    dijkstra1(1,dist1,trace1), dijkstra1(n,distN,traceN);
    if(dist1[n]<1e9&&distN[1]<1e9) rs=min(rs,dist1[n]+distN[1]);
    if(dist1[n]<1e9){
        for(int i = n; i>1; i=trace1[i].from)
            vis[trace1[i].pos]=1, v.pb(trace1[i].pos);
    }
    if(distN[1]<1e9){
        for(int i = 1; i<n; i=traceN[i].from)
            vis[traceN[i].pos]=1, v.pb(traceN[i].pos);
    }
    dijkstrarev(1,distrev1), dijkstrarev(n,distrevN);
    for(int i = 1; i<=m; ++i)
        if(!vis[i]){
            int a=dist1[n],b=distN[1];
            a=min(a,dist1[edge[i].to]+distrevN[edge[i].from]+edge[i].weight);
            b=min(b,distN[edge[i].to]+distrev1[edge[i].from]+edge[i].weight);
            if(a<1e9&&b<1e9) rs=min(rs,a+b+edge[i].cost);
        }
    for(int& x : v){
        inv[x]=1;
        dijkstra2(1,dist1), dijkstra2(n,distN);
        if(dist1[n]<1e9&&distN[1]<1e9) rs=min(rs,dist1[n]+distN[1]+edge[x].cost);
        inv[x]=0;
    }
    if(rs>=2e9) cout << -1;
    else cout << rs;
}

컴파일 시 표준 에러 (stderr) 메시지

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:3:19: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t4.cpp:79:45: note: in expansion of macro 'fo'
   79 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~
ho_t4.cpp:3:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |                                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t4.cpp:79:45: note: in expansion of macro 'fo'
   79 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 63 / 63