Submission #1292403

#	Time	Username	Problem	Language	Result	Execution time	Memory
1292403		khoal	Robot (JOI21_ho_t4)	C++20	0 / 100	84 ms	13920 KiB

Main

#include <iostream>
#include <climits>
#include <queue>
#include <fstream>

using namespace std;
const int N=1e5+5;
const long long INF=1e18;

struct E{
    int v, c, w;
    void tie(int &_v, int &_c, int &_w)
    {
        _v=v;
        _c=c;
        _w=w;
    }
};
vector<E>g[N];
int n, m, u, v, c, w;
long long d[N], ans[2*N], sum[2*N], tmp;
priority_queue<pair<long long,int>,vector<pair<long long,int>>,greater<pair<long long,int>>>q;
void bfs()
{
    for(int i=1;i<=n;i++)
        d[i]=INF;
    for(int i=1;i<=m;i++)
        ans[i]=INF;
    d[1]=0;
    q.push({0,1});
    while(!q.empty())
    {
        auto [du,u]=q.top();
        q.pop();
        if(du!=d[u])
            continue;
        for(auto &e:g[u])
        {
            e.tie(v,c,w);
            sum[c]+=w;
            ans[c]=max(ans[c],d[v]);
        }
        for(auto &e:g[u])
        {
            e.tie(v,c,w);
            tmp=min(1LL*w,sum[c]-w);
            if(d[v]>du+tmp)
            {
                d[v]=du+tmp;
                q.push({d[v],v});
            }
            if(d[v]>ans[c]+sum[c]-w)
            {
                d[v]=ans[c]+sum[c]-w;
                q.push({d[v],v});
            }
        }
        for(auto &e:g[u])
        {
            sum[e.c]=0;
            ans[e.c]=INF;
        }
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if(fopen("robot1.inp", "r")) {
        freopen("robot1.inp", "r", stdin);
        freopen("robot1.out", "w", stdout); }
    cin>>n>>m;
    while(m--)
    {
        cin>>u>>v>>c>>w;
        g[u].push_back({v,c,w});
        g[v].push_back({u,c,w});
    }
    bfs();
    cout<<(d[n]==INF?-1:d[n]);
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen("robot1.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen("robot1.out", "w", stdout); }
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42