Submission #303234

#	Time	Username	Problem	Language	Result	Execution time	Memory
303234		zaneyu	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	468 ms	27880 KiB

commuter_pass

/*input
8 8
5 7
6 8
1 2 2
2 3 3
3 4 4
1 4 1
1 5 5
2 6 6
3 7 7
4 8 8
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<pair<int,int>, null_type, less<pair<int,int>>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#pragma GCC optimize("unroll-loops,no-stack-protector")
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;
#define ld double
#define pii pair<ll,ll>
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=2e5+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=998244353;
const ld PI=3.14159265358979323846;
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
#define MP make_pair
ll mult(ll a,ll b){
    return (a*b)%MOD;
}
ll mypow(ll a,ll b){
    ll res=1LL;
    while(b){
        if(b&1) res=res*a%MOD;
        a=a*a%MOD;
        b>>=1;
    }
    return res;
}
vector<pii> v[maxn];
int n,m;
void dij(int u,ll dist[]){
    REP(i,n) dist[i]=INF64;
    dist[u]=0;
    priority_queue<pii,vector<pii>,greater<pii>> pq;
    pq.push({0,u});
    while(!pq.empty()){
        int z=pq.top().s;
        pq.pop();
        for(auto x:v[z]){
            if(dist[x.f]>dist[z]+x.s){
                dist[x.f]=dist[z]+x.s;
                pq.push({dist[x.f],x.f});
            }
        }
    }
}
ll ds[maxn],dt[maxn],da[maxn],db[maxn];
ll dp[maxn];
ll ans=INF64;
int s,t,a,b;
ll dfs(int u,ll mn){
    if(dp[u]!=-1) return dp[u];
    if(u==t){
        return db[t];
    }
    ll mb=db[u];
    MNTO(mn,da[u]);
    for(auto x:v[u]){
        if(ds[u]+x.s+dt[x.f]==ds[t]){
            MNTO(mb,dfs(x.f,mn));
        }
    }
    dp[u]=mb;
    MNTO(ans,mb+mn);
    return dp[u];
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0);
    cin>>n>>m;
    
    cin>>s>>t>>a>>b;
    --s;
    --t;
    --a;
    --b;
    REP(i,m){
        int a,b,c;
        cin>>a>>b>>c;
        --a;
        --b;
        v[a].pb({b,c});
        v[b].pb({a,c});
    }

    dij(s,ds);
    dij(t,dt);
    dij(a,da);
    dij(b,db);
    ans=da[b];
    REP(i,n) dp[i]=-1;
    dfs(s,ds[a]);
    swap(da,db);
    swap(a,b);
    REP(i,n) dp[i]=-1;
    dfs(s,ds[a]);
    cout<<ans<<'\n';
} 

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