Submission #1012216

#	Time	Username	Problem	Language	Result	Execution time	Memory
1012216		codefox	Robot (JOI21_ho_t4)	C++14	0 / 100	21 ms	6740 KiB

Main

#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast")

#define int long long
#define arr array<int, 4>

vector<vector<arr>> graph;
vector<int> fc;
vector<int> d1;
vector<int> d2;

int32_t main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, m;
    cin >> n >> m;

    graph.assign(n, vector<arr>());
    fc.assign(n, -1);
    d1.assign(n, 1e18);
    d2.assign(n, 1e18);

    for (int j = 0; j < m; j++)
    {
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        a--; b--; c--;
        graph[a].push_back({b, c, d, 0});
    }

    priority_queue<arr, vector<arr>, greater<arr>> pq;
    pq.push({0, m+1, 0, 0});
    while (pq.size())
    {
        arr a = pq.top();
        pq.pop();
        int i = a[2];
        int c = a[1];
        int d = a[0];
        int p = a[3];
        if (fc[i]==c) continue;
        if (fc[i]==-1) 
        {
            fc[i] = c;
            d1[i] = d;
        }
        else 
        {
            if (d2[i]<=d) continue;
            d2[i] = d;
        }
        map<int, int> cost;
        for (arr ele:graph[i])
        {
            if (ele[0]==p) cost[c] +=ele[2];
            else cost[ele[1]] += ele[2];
        }
        int ava1 = -1;
        int ava2 = -1;
        int ava3 = -1;
        int avac1 = 0;
        int avac2 = 0;
        int avac3 = 0;
        for (int j = 0; j < m; j++)
        {
            if (cost[j]==0) 
            {
                if (ava1==-1) ava1 = j;
                else if (ava2==-1) ava2=j;
                else 
                {
                    ava3 = j;
                    break;
                }
            }
        }
        if (ava1==-1) avac1=1e18;
        if (ava2==-1) avac2=1e18;
        if (ava3==-1) avac3=1e18;
        for (arr ele:graph[i])
        {
            if (cost[ele[1]]<avac1)
            {
                ava3 = ava2;
                avac3 = avac2;
                ava2 = ava1;
                avac2 = avac1;
                avac1=cost[ele[1]];
                ava1=ele[1];
            }
            else if (cost[ele[1]]<avac2)
            {
                ava3 = ava2;
                avac3 = avac2;
                ava2 = ele[1];
                avac2=cost[ele[1]];
            }
            else if (cost[ele[1]]<avac3)
            {
                ava3=ele[1];
                avac3=cost[ele[1]];
            }
        }
        for (arr ele:graph[i])
        {
            if (ele[0]==p) continue;
            pq.push({d+cost[ele[1]]-ele[2], ele[1], ele[0], i});
            if (ava1!=-1) pq.push({d+ele[2]+avac1, ava1, ele[0], i});
            if (ava2!=-1) pq.push({d+ele[2]+avac2, ava2, ele[0], i});
            if (ava3!=-1) pq.push({d+ele[2]+avac3, ava3, ele[0], i});
        }
    }
    if (d1[n-1]==1e18) cout << -1;
    else cout << d1[n-1];
    return 0;
}

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