Submission #693121

#	Time	Username	Problem	Language	Result	Execution time	Memory
693121		guagua0407	Robot (JOI21_ho_t4)	C++17	34 / 100	3088 ms	61340 KiB

Main

/*
我是不是要給自己設定一個想題目的時間
hard - 50 分鐘
medium - 30 分鐘
easy - 15 分鐘
*/
#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll,ll>
#define f first
#define s second
#define all(x) x.begin(),x.end() 
#define sz(x) (ll)(x.size())
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const ll mxn=1e5+5;
vector<pair<ll,pair<ll,ll>>> adj[mxn];
unordered_map<ll,ll> csum[mxn];
ll ans[mxn];
unordered_map<ll,ll> ans2[mxn];

int main() {_
    //setIO("wayne");
    // 1. change edge
    // 2. change other edges
    // 3. change edge and leave next node by edge with same color
    ll n,m;
    cin>>n>>m;
    for(ll i=0;i<m;i++){
        ll a,b,c,w;
        cin>>a>>b>>c>>w;
        adj[a].push_back({b,{c,w}});
        adj[b].push_back({a,{c,w}});
        csum[a][c]+=w;
        csum[b][c]+=w;
    }
    //{-cost,node,color(if case3)}
    priority_queue<pair<ll,pair<ll,ll>>> pq;
    pq.push({0,{1,0}});
    for(ll i=1;i<=n;i++) ans[i]=(ll)(1e18);
    ans[1]=0;
    while(!pq.empty()){
        ll val;
        ll v,c;
        auto tmp=pq.top();
        pq.pop();
        val=tmp.f*-1;
        v=tmp.s.f;
        c=tmp.s.s;
        if(v==n and c==0){
            cout<<val;
            return 0;
        }
        if(c){
            if(ans2[v][c]!=val) continue;
            for(auto u:adj[v]){
                if(u.s.f!=c) continue;
                ll res=val+csum[v][c]-u.s.s;
                if(res<ans[u.f]){
                    ans[u.f]=res;
                    pq.push({-ans[u.f],{u.f,0}});
                }
            }
        }
        else{
            if(ans[v]!=val) continue;
            for(auto u:adj[v]){
                ll val1=val+u.s.s;
                if(val1<ans[u.f]){
                    ans[u.f]=val1;
                    pq.push({-ans[u.f],{u.f,0}});
                }
                ll val2=val+csum[v][u.s.f]-u.s.s;
                if(val2<ans[u.f]){
                    ans[u.f]=val2;
                    pq.push({-ans[u.f],{u.f,0}});
                }
                ll val3=val;
                if(ans2[u.f].count(u.s.f)==0 or val3<ans2[u.f][c]){
                    ans2[u.f][u.s.f]=val3;
                    pq.push({-ans2[u.f][u.s.f],{u.f,u.s.f}});
                }
            }
        }
    }
    cout<<-1;
    return 0;
}
//maybe its multiset not set

Compilation message (stderr)

Main.cpp: In function 'void setIO(std::string)':
Main.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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