Submission #527639

#	Time	Username	Problem	Language	Result	Execution time	Memory
527639		Lobo	Olympic Bus (JOI20_ho_t4)	C++17	100 / 100	313 ms	6112 KiB

ho_t4

#include<bits/stdc++.h>
using namespace std;
 
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
 
#define maxn 210
#define maxm 50010
 
int n, m, d[maxn][maxn], dx1[maxn][maxn], dxn[maxn][maxn], dxi1[maxn][maxn], dxin[maxn][maxn];
pair<int,int> mn1[maxn], mnn[maxn];
int u[maxm], v[maxm], c[maxm], up[maxm], mark[maxn];
vector<int> g[maxn],gi[maxn];
 
void shpx1(int x) {
    for(int i = 1; i <= n; i++) {
        dx1[x][i] = inf;
        mark[i] = 0;
    }
 
    dx1[x][1] = 0;
        
    if(x == 1) return;
    int cnt = n;
    while(cnt--) {
        int a;
        int dist = inf;
        for(int i = 1; i <= n; i++) {
            if(!mark[i] && dx1[x][i] < dist) {
                dist = dx1[x][i];
                a = i;
            }
        }

        if(dist == inf) return;
        mark[a] = 1;

        for(auto i : g[a]) {
            int b = v[i];
            int w = c[i];
            if(b == x) continue;
 
            if(dx1[x][b] > dx1[x][a] + w) {
                dx1[x][b] = dx1[x][a] + w;
            }
        }
    }
}

void shpxi1(int x) {
    for(int i = 1; i <= n; i++) {
        dxi1[x][i] = inf;
        mark[i] = 0;
    }
 
    dxi1[x][1] = 0;
        
    if(x == 1) return;
    int cnt = n;
    while(cnt--) {
        int a;
        int dist = inf;
        for(int i = 1; i <= n; i++) {
            if(!mark[i] && dxi1[x][i] < dist) {
                dist = dxi1[x][i];
                a = i;
            }
        }

        if(dist == inf) return;
        mark[a] = 1;

        for(auto i : gi[a]) {
            int b = u[i];
            int w = c[i];
            if(b == x) continue;
 
            if(dxi1[x][b] > dxi1[x][a] + w) {
                dxi1[x][b] = dxi1[x][a] + w;
            }
        }
    }
}

void shpxin(int x) {
    for(int i = 1; i <= n; i++) {
        dxin[x][i] = inf;
        mark[i] = 0;
    }
 
    dxin[x][n] = 0;
        
    if(x == n) return;
    int cnt = n;
    while(cnt--) {
        int a;
        int dist = inf;
        for(int i = 1; i <= n; i++) {
            if(!mark[i] && dxin[x][i] < dist) {
                dist = dxin[x][i];
                a = i;
            }
        }

        if(dist == inf) return;
        mark[a] = 1;
        for(auto i : gi[a]) {
            int b = u[i];
            int w = c[i];
            if(b == x) continue;
 
            if(dxin[x][b] > dxin[x][a] + w) {
                dxin[x][b] = dxin[x][a] + w;
            }
        }
    }
}
 
 
void shpxn(int x) {
    for(int i = 1; i <= n; i++) {
        dxn[x][i] = inf;
        mark[i] = 0;
    }
 
    dxn[x][n] = 0;
        
    if(x == n) return;
    int cnt = n;
    while(cnt--) {
        int a;
        int dist = inf;
        for(int i = 1; i <= n; i++) {
            if(!mark[i] && dxn[x][i] < dist) {
                dist = dxn[x][i];
                a = i;
            }
        }

        if(dist == inf) return;
        mark[a] = 1;
        for(auto i : g[a]) {
            int b = v[i];
            int w = c[i];
            if(b == x) continue;
 
            if(dxn[x][b] > dxn[x][a] + w) {
                dxn[x][b] = dxn[x][a] + w;
            }
        }
    }
}
 
void solve() {
    cin >> n >> m;
 
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            d[i][j] = inf;
        }
    }

    for(int i = 1; i <= n; i++) {
        d[i][i] = 0;
    }
 
    for(int i = 1; i <= m; i++) {
        cin >> u[i] >> v[i] >> c[i] >> up[i];
        g[u[i]].pb(i);
        gi[v[i]].pb(i);
 
        d[u[i]][v[i]] = min(d[u[i]][v[i]],c[i]);
    }
 
    for(int k = 1; k <= n; k++) {
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= n; j++) {
                d[i][j] = min(d[i][j],d[i][k]+d[k][j]);
            }
        }
    }
 
    //tenho que pegar dx1 e dxn
    for(int i = 1; i <= n; i++) {
        shpx1(i);
        shpxn(i);
        shpxi1(i);
        shpxin(i);
    }

    //pegar o menor/segundo menor de cada cara
 
    for(int a = 1; a <= n; a++) {
        mn1[a] = mp(inf,inf);
        if(a == n) mn1[a] = mp(0,0);
 
        for(auto i : g[a]) {
            int b = v[i];
 
            mn1[a].sc = min(mn1[a].sc, dx1[b][a] + c[i] + dxin[a][b]);
 
            if(mn1[a].sc < mn1[a].fr) swap(mn1[a].fr,mn1[a].sc);
        }
 
    }
    
    for(int a = 1; a <= n; a++) {
        mnn[a] = mp(inf,inf);
        if(a == 1) mnn[a] = mp(0,0);
 
        for(auto i : g[a]) {
            int b = v[i];
 
            mnn[a].sc = min(mnn[a].sc, dxn[b][a] + c[i] + dxi1[a][b]);
 
            if(mnn[a].sc < mnn[a].fr) swap(mnn[a].fr,mnn[a].sc);
        }
    }
 
    int ans = inf;
    ans = min(ans, d[1][n]+d[n][1]);
 
    //usa no 1->n
    for(int i = 1; i <= m; i++) {
        int ans1 = 0;
 
        if(d[n][1] == d[n][u[i]] + c[i] + d[v[i]][1]) {
            ans1 = min(dxn[u[i]][1], mnn[u[i]].sc);
        }
        else {
            ans1 = d[n][1];
        }
        
        ans1 = min(ans1,dxn[u[i]][v[i]]+c[i]+dxi1[v[i]][u[i]]);
        //d(n,v[i]) sem passar pro u[i]
        //d(u[i],1) sem passar por v[i]
        ans1+= dx1[u[i]][v[i]] + c[i] + up[i] + dxin[v[i]][u[i]];
        ans = min(ans,ans1);
    }
 
    //usa no n->1
    for(int i = 1; i <= m; i++) {
        int ans1 = 0;
 
        if(d[1][n] == d[1][u[i]] + c[i] + d[v[i]][n]) {
            ans1 = min(dx1[u[i]][n], mn1[u[i]].sc);
        }
        else {
            ans1 = d[1][n];
        }
        
        ans1 = min(ans1,dx1[u[i]][v[i]]+c[i]+dxin[v[i]][u[i]]);
        ans1+= dxn[u[i]][v[i]] + c[i] + up[i] + dxi1[v[i]][u[i]];
        ans = min(ans,ans1);
    }
 
    if(ans == inf) cout << -1 << endl;
    else cout << ans << endl;
 
}
 
int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);
 
    // freopen("in.in", "r", stdin);
    //freopen("out.out", "w", stdout);
    
    int tt = 1;
    // cin >> tt;
    while(tt--) solve();
 
}

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