제출 #1087247

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1087247		lftroq	Robot (JOI21_ho_t4)	C++14	100 / 100	716 ms	84416 KiB

Main

#include<bits/stdc++.h>
#define endl '\n'
#define fi first
#define se second
using namespace std;
typedef long double ld;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> llll;

const ll INF=1e18;
const int N=1e5+5;

struct edge
{
    int v,c;
    ll p;
};

/**
- Can always change an edge to another random color
- Call the random color 0 (can ignore it -> put into dp[u])

Init:
- dp[u]: minimum to get to u
- dp1[u][c]: minimum to get to u, last color is c, didn't count cost to change color of that edge
- ps[u][c]: sum of edge with 1 node is u and color c

If move from color c (c != 0): must move to u with color c -> change all same color edge 
If move from color 0:
- Case 1: change all same color edge
- Case 2: change this edge, not all same color edge
- Case 3: move -> dp1[u][c]
**/

map<int,vector<edge>> graph[N];
ll dp[N];
map<int,ll> dp1[N],ps[N];

void solve()
{
    int n,m;
    cin >> n >> m;
    for(int i=1;i<=m;i++)
    {
        int u,v,c;
        ll p;
        cin >> u >> v >> c >> p;
        graph[u][c].push_back({v,c,p});
        graph[v][c].push_back({u,c,p});
        ps[u][c]+=p;
        ps[v][c]+=p;
    }
    for(int i=1;i<=n;i++) dp[i]=INF;
    dp[1]=0;
    priority_queue<pair<ll,pii>,vector<pair<ll,pii>>,greater<pair<ll,pii>>> pq;
    pq.push({0,{1,0}});
    while((int)pq.size())
    {
        ll temp=pq.top().fi;
        int u=pq.top().se.fi,c=pq.top().se.se;
        pq.pop();
        if(c)
        {
            if(dp1[u][c]!=temp) continue;
            for(int i=0;i<(int)graph[u][c].size();i++)
            {
                edge e=graph[u][c][i];
                ll w1=ps[u][c]-e.p;
                if(dp1[u][c]+w1<dp[e.v])
                {
                    dp[e.v]=w1+dp1[u][c];
                    pq.push({dp[e.v],{e.v,0}});
                }
            }
        }
        else
        {
            if(dp[u]!=temp) continue;
            for(map<int,vector<edge>>::iterator it=graph[u].begin();it!=graph[u].end();it++)
            {
                for(int i=0;i<(int)it->se.size();i++)
                {
                    edge e=it->se[i];
                    ll w1=ps[u][e.c]-e.p,w2=e.p;
                    if(dp[u]+min(w1,w2)<dp[e.v])
                    {
                        dp[e.v]=dp[u]+min(w1,w2);
                        pq.push({dp[e.v],{e.v,0}});
                    }
                    if(!dp1[e.v].count(e.c)||dp[u]<dp1[e.v][e.c])
                    {
                        dp1[e.v][e.c]=dp[u];
                        pq.push({dp1[e.v][e.c],{e.v,e.c}});
                    }
                }
            }
        }
    }
    if(dp[n]>=INF) dp[n]=-1;
    cout << dp[n] << endl;
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //freopen("hanhhhh.inp","r",stdin);
    //freopen("hanhhhh.out","w",stdout);
    int t=1;
    //cin >> t;
    while(t--)
    solve();
    return 0;
}

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