Submission #479831

#	Time	Username	Problem	Language	Result	Execution time	Memory
479831		Yuisuyuno	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	567 ms	31388 KiB

commuter_pass

//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 100005
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"
#define int long long

using namespace std;

typedef long double ld;
typedef int ll;
const int inf = LLONG_MAX/2;
const int minf = -1e10;

int n, m;
int s, t, u, v;
vector<ii> g[N];
int ds[N], dv[N], du[N];
bool vst[N];
int ans;
int dp[3][N];

void readfile()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if (fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        //freopen(Task".out","w",stdout);
    }
    cin >> n >> m >> s >> t >> u >> v;
    for(int i=1; i<=m; i++){
        int u, v, z;
        cin >> u >> v >> z;
        g[u].pb(ii(v,z));
        g[v].pb(ii(u,z));
    }
}

void dijkstra1(ll start, ll arr[]) {
	fill(vst, vst + 100001, false);

	priority_queue<pair<ll, ll>> pq;
	pq.push({0, start});
	while (!pq.empty()) {
		ll c, node;
		tie(c, node) = pq.top();
		pq.pop();

		if (!vst[node]) {
			arr[node] = -c;
			vst[node] = true;
			for (auto& i : g[node]) pq.push({c - i.second, i.first});
		}
	}
}

void djk2(int st, int en){
    fill(vst, vst+100001, false);
    fill(dp[0], dp[0]+100001, inf);
    fill(dp[1], dp[1]+100001, inf);

    priority_queue<pair<int,pair<int,int>>> q;
    q.push({0,{st,0}});
    dp[0][0] = dp[1][0] = inf;
    while (q.size()){
        int node, c, par;
        ii temp;
        tie(c,temp) = q.top();
        tie(node,par) = temp;
        q.pop();
        if (!vst[node]){
            vst[node] = 1;
            ds[node] = -c;
            dp[0][node] = min(dp[0][par],du[node]);
            dp[1][node] = min(dp[1][par],dv[node]);
            for(auto &i : g[node]) q.push({c-i.se,{i.fi,node}});
        }
        else if (-c == ds[node]){
            int tmp1 = min(dp[0][par],du[node]);
            int tmp2 = min(dp[1][par],dv[node]);
            if (tmp1 + tmp2 < dp[0][node]+dp[1][node]){
                dp[0][node] = tmp1;
                dp[1][node] = tmp2;
            }
        }
    }
    ans = min(ans,dp[0][en]+dp[1][en]);
}

void proc()
{
    dijkstra1(u,du);
    dijkstra1(v,dv);
    ans = du[v];
    djk2(s,t);
    djk2(t,s);
    cout << ans;
}

signed main()
{
    readfile();
    proc();
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void readfile()':
commuter_pass.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen(Task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45