Submission #444613

#	Time	Username	Problem	Language	Result	Execution time	Memory
444613		zaneyu	Olympic Bus (JOI20_ho_t4)	C++14	100 / 100	291 ms	2964 KiB

ho_t4

/*input
4 5
1 2 4 4
1 3 2 1
4 3 1 2
4 1 6 1
2 4 2 5
*/
#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<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=double;
using pii=pair<int,int>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int 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()
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
const ll INF64=1e18+1;
const int INF=0x3f3f3f3f;
const int MOD=1e9+7;
const ld PI=acos(-1);
const ld eps=1e-6;
#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)
inline ll mult(ll a,ll b){
    if(a>=MOD) a%=MOD;
    if(b>=MOD) b%=MOD;
    return (a*b)%MOD;
}
inline ll mypow(ll a,ll b){
    if(b<=0) return 1;
    ll res=1LL;
    while(b){
        if(b&1) res=mult(res,a);
        a=mult(a,a);
        b>>=1;
    }
    return res;
}
const int maxn=200+5;
const int maxlg=__lg(maxn)+2;
vector<int> vv[maxn];
vector<pair<pii,pii>> v;
ll d[maxn];
bool in[maxn];
int n;
ll dij(int s,int t){
    REP(i,n) d[i]=INF64,in[i]=0;
    d[s]=0;
    REP(asd,n){
        int p=-1;
        REP(i,n) if(!in[i] and (d[i]<d[p] or p==-1)) p=i;
        in[p]=1;
        for(auto x:vv[p]){
            int b=v[x].f.s;
            MNTO(d[b],d[p]+v[x].s.f);
        }
    }
    return d[t];
}
ll dist[maxn][maxn];
int32_t main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int m;
    cin>>n>>m;
    REP(i,n) REP(j,n) dist[i][j]=INF64;
    REP(i,n) dist[i][i]=0;
    REP(i,m){
        int a,b,c,d;
        cin>>a>>b>>c>>d;
        --a,--b;
        MNTO(dist[a][b],c);
        vv[a].pb(i);
        v.pb({{a,b},{c,d}});
    } 
    REP(k,n){ 
        REP(i,n){
            REP(j,n){
                MNTO(dist[i][j],dist[i][k]+dist[k][j]);
            }
        }
    }
    ll ans=INF64;
    MNTO(ans,dist[0][n-1]+dist[n-1][0]);
    REP(i,m){
        auto x=v[i];
        int a=x.f.f,b=x.f.s,c=x.s.f,d=x.s.s;
        ll d1=min(dist[0][n-1],dist[0][b]+c+dist[a][n-1]),d2=min(dist[n-1][0],dist[n-1][b]+c+dist[a][0]);
        if(d1+d2+d<ans){
            vv[a].erase(find(ALL(vv[a]),i));
            vv[b].pb(i);
            swap(v[i].f.f,v[i].f.s);
            ll xx=dij(0,n-1),yy=dij(n-1,0);
            MNTO(ans,xx+yy+d);
            swap(v[i].f.f,v[i].f.s);
            vv[b].pop_back();
            vv[a].pb(i);
        }
    }
    if(ans==INF64) ans=-1;
    cout<<ans;
}  

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 63 / 63