oj.uz

답안 #393537

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
393537 2021-04-23T20:14:46 Z nohaxjustsoflo Commuter Pass (JOI18_commuter_pass) C++17
100 / 100
 854 ms 56872 KB 
#include <bits/stdc++.h>
typedef long long ll;

using namespace std;
const int mxN = 1e5+5;
const int mxM = 2e5+5;

struct edge
{
    int u, v;
    ll c;
    int rev;
};

vector<int> out[mxN];
vector<int> in[mxN];
vector<int> new_out[mxN];
vector<int> new_in[mxN];
edge edges[2*mxM];
ll best[mxN];
bool ok[mxN]; ///vertices on shortest path
bool done[mxN];
bool cut[2*mxM];

bool fix(int i, int t)
{
    if(i == t) return true;
    if(done[i]) return ok[i];
    done[i] = true;
    for(int e : out[i])
    {
        int j = edges[e].v;
        if(cut[e]) continue;
        if(fix(j, t))
        {
            ok[i]=1;
            new_out[i].push_back(e);
            new_in[j].push_back(edges[e].rev);
        }
    }
    return ok[i];
}

/// node, used, using, direction
ll dp[mxN][2][2][2];

struct pos
{
    int i, used, cur, dir;
    bool operator<(const pos& p) const
    {
        return i < p.i;
    }
};

ll solve(int u, int v)
{
    for(int i = 0; i < mxN; i++)
        for(int j = 0; j < 2; j++)
            for(int k = 0; k < 2; k++)
                dp[i][j][k][0] = dp[i][j][k][1] = 1e18;

    ll ans = 1e18;
    dp[u][0][0][0] = 0;
    priority_queue<pair<ll, pos>> q;
    q.push({0, {u, 0, 0, 0}});
    while(!q.empty())
    {
        auto par = q.top(); q.pop();
        pos p = par.second;
        int i = p.i;
        ll cost = -par.first;
        if(cost > dp[p.i][p.used][p.cur][p.dir]) continue;
        if(i == v)
        {
            ans = min(ans, cost);
            continue;
        }
        if(!p.used)
        {
            if(!p.cur || !p.dir)
            {
                for(auto e : new_out[i]) ///kreni u 0 dir
                {
                    int j = edges[e].v;
                    if(cost < dp[j][0][1][0])
                    {
                        dp[j][0][1][0] = cost;
                        q.push({-cost, {j, 0, 1, 0}});
                    }
                }
            }
            if(!p.cur || p.dir)
            {
                for(auto e : new_in[i]) ///kreni u 1 dir
                {
                    int j = edges[e].v;
                    if(cost < dp[j][0][1][1])
                    {
                        dp[j][0][1][1] = cost;
                        q.push({-cost, {j, 0, 1, 1}});
                    }
                }
            }
            if(p.cur)
            {
                for(auto e : out[i]) ///canceluj
                {
                    int j = edges[e].v;
                    if(cost + edges[e].c < dp[j][1][0][0])
                    {
                        dp[j][1][0][0] = cost + edges[e].c;
                        q.push({-dp[j][1][0][0], {j,1,0,0}});
                    }
                }
            }
            else
            {
                for(auto e : out[i]) ///klasicno samo nastavi !used
                {
                    int j = edges[e].v;
                    if(cost + edges[e].c < dp[j][0][0][0])
                    {
                        dp[j][0][0][0] = cost + edges[e].c;
                        q.push({-dp[j][0][0][0], {j,0,0,0}});
                    }
                }
            }
        }
        else
        {
            for(auto e : out[i]) ///klasicno samo nastavi used
            {
                int j = edges[e].v;
                if(cost + edges[e].c < dp[j][1][0][0])
                {
                    dp[j][1][0][0] = cost + edges[e].c;
                    q.push({-dp[j][1][0][0], {j,1,0,0}});
                }
            }
        }
    }
    return ans;
}

int main()
{
    for(int i = 0; i < mxN; i++) best[i] = 1e18;
    int n, m;
    cin >> n >> m;
    int s, t, U, V;
    cin >> s >> t >> U >> V;
    for(int i = 0; i < m; i++)
    {
        int u, v; ll c; cin >> u >> v >> c;
        edges[i*2] = {u,v,c,i*2+1};
        edges[i*2+1] = {v,u,c,i*2};
        out[u].push_back(i*2);
        in[u].push_back(i*2+1);
        out[v].push_back(i*2+1);
        in[v].push_back(i*2);
    }
    best[s] = 0;
    ///cost, to, edge
    priority_queue<pair<ll, int>> q;
    q.push({0, s});
    while(!q.empty())
    {
        auto cur = q.top(); q.pop();
        int i = cur.second;
        int cost = -cur.first;
        if(cost > best[i]) continue;
        for(auto e : in[i])
        {
            int u = edges[e].u, v = i;
            ll c = edges[e].c;
            if(best[u] + c > best[v]) cut[e] = true;
        }
        for(auto e : out[i])
        {
            int u = i, v = edges[e].v;
            ll c = edges[e].c;
            if(best[u] + c < best[v])
            {
                best[v] = best[u] + c;
                q.push({-best[v], v});
            }
        }
    }
    fix(s, t);
    /*for(int i = 1; i <= n; i++)
    {
        cout << "node " << i << "\n";
        for(int e : new_out[i])
        {
            cout << edges[e].c << " ";
        }
        cout << "\n";
    }
    cout << "*********************************\n";
    for(int i = 1; i <= n; i++)
    {
        cout << "node " << i << "\n";
        for(int e : new_in[i])
        {
            cout << edges[e].u << edges[e].v << " ";
        }
        cout << "\n";
    }
    cout<<"\n\n";*/
    cout << solve(U, V);
}
/*
6 6
1 6
1 4
1 2 1
2 3 1
3 5 1
2 4 3
4 5 2
6 5 1

4 4
1 4
0 0
1 2 1
1 3 1
2 4 1
3 4 1
*/

Subtask #1
16.0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Correct 619 ms 47740 KB Output is correct
2 Correct 690 ms 44540 KB Output is correct
3 Correct 789 ms 56872 KB Output is correct
4 Correct 588 ms 43744 KB Output is correct
5 Correct 741 ms 48548 KB Output is correct
6 Correct 614 ms 47656 KB Output is correct
7 Correct 751 ms 49728 KB Output is correct
8 Correct 737 ms 49072 KB Output is correct
9 Correct 683 ms 43944 KB Output is correct
10 Correct 668 ms 43948 KB Output is correct
11 Correct 369 ms 40736 KB Output is correct
12 Correct 701 ms 43852 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 719 ms 47564 KB Output is correct
2 Correct 703 ms 47912 KB Output is correct
3 Correct 708 ms 49964 KB Output is correct
4 Correct 707 ms 47628 KB Output is correct
5 Correct 752 ms 48916 KB Output is correct
6 Correct 790 ms 55636 KB Output is correct
7 Correct 798 ms 56852 KB Output is correct
8 Correct 697 ms 47968 KB Output is correct
9 Correct 746 ms 48824 KB Output is correct
10 Correct 710 ms 47068 KB Output is correct
11 Correct 417 ms 44084 KB Output is correct
12 Correct 738 ms 56464 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 34 ms 18952 KB Output is correct
2 Correct 10 ms 16716 KB Output is correct
3 Correct 11 ms 16760 KB Output is correct
4 Correct 55 ms 21060 KB Output is correct
5 Correct 32 ms 18844 KB Output is correct
6 Correct 11 ms 16844 KB Output is correct
7 Correct 12 ms 16940 KB Output is correct
8 Correct 16 ms 17152 KB Output is correct
9 Correct 11 ms 16944 KB Output is correct
10 Correct 40 ms 18816 KB Output is correct
11 Correct 10 ms 16716 KB Output is correct
12 Correct 10 ms 16716 KB Output is correct
13 Correct 10 ms 16844 KB Output is correct
14 Correct 10 ms 16844 KB Output is correct
15 Correct 11 ms 16768 KB Output is correct

Subtask #4
45.0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 619 ms 47740 KB Output is correct
2 Correct 690 ms 44540 KB Output is correct
3 Correct 789 ms 56872 KB Output is correct
4 Correct 588 ms 43744 KB Output is correct
5 Correct 741 ms 48548 KB Output is correct
6 Correct 614 ms 47656 KB Output is correct
7 Correct 751 ms 49728 KB Output is correct
8 Correct 737 ms 49072 KB Output is correct
9 Correct 683 ms 43944 KB Output is correct
10 Correct 668 ms 43948 KB Output is correct
11 Correct 369 ms 40736 KB Output is correct
12 Correct 701 ms 43852 KB Output is correct
13 Correct 719 ms 47564 KB Output is correct
14 Correct 703 ms 47912 KB Output is correct
15 Correct 708 ms 49964 KB Output is correct
16 Correct 707 ms 47628 KB Output is correct
17 Correct 752 ms 48916 KB Output is correct
18 Correct 790 ms 55636 KB Output is correct
19 Correct 798 ms 56852 KB Output is correct
20 Correct 697 ms 47968 KB Output is correct
21 Correct 746 ms 48824 KB Output is correct
22 Correct 710 ms 47068 KB Output is correct
23 Correct 417 ms 44084 KB Output is correct
24 Correct 738 ms 56464 KB Output is correct
25 Correct 34 ms 18952 KB Output is correct
26 Correct 10 ms 16716 KB Output is correct
27 Correct 11 ms 16760 KB Output is correct
28 Correct 55 ms 21060 KB Output is correct
29 Correct 32 ms 18844 KB Output is correct
30 Correct 11 ms 16844 KB Output is correct
31 Correct 12 ms 16940 KB Output is correct
32 Correct 16 ms 17152 KB Output is correct
33 Correct 11 ms 16944 KB Output is correct
34 Correct 40 ms 18816 KB Output is correct
35 Correct 10 ms 16716 KB Output is correct
36 Correct 10 ms 16716 KB Output is correct
37 Correct 10 ms 16844 KB Output is correct
38 Correct 10 ms 16844 KB Output is correct
39 Correct 11 ms 16768 KB Output is correct
40 Correct 622 ms 47944 KB Output is correct
41 Correct 626 ms 42520 KB Output is correct
42 Correct 635 ms 42368 KB Output is correct
43 Correct 432 ms 45112 KB Output is correct
44 Correct 476 ms 45096 KB Output is correct
45 Correct 854 ms 51372 KB Output is correct
46 Correct 800 ms 51176 KB Output is correct
47 Correct 603 ms 43440 KB Output is correct
48 Correct 475 ms 41020 KB Output is correct
49 Correct 526 ms 47364 KB Output is correct
50 Correct 806 ms 50216 KB Output is correct
51 Correct 844 ms 51580 KB Output is correct