Submission #1259867

#	Time	Username	Problem	Language	Result	Execution time	Memory
1259867		nguyenhuythach	Toll (BOI17_toll)	C++20	0 / 100	70 ms	87620 KiB

toll

#include<bits/stdc++.h>
#include<algorithm>
#include<random>
#include<chrono>
#include<cstdlib>
#include<ctime>
#include<numeric>
#include<vector>
#include<stack>
#include<map>
#include<set>
#include<queue>
#include<iomanip>
#define int long long
#define ll long long
#define L LLONG_MAX
#define fi first
#define se second
#define pii pair<int,int>
#define sz(a) ((int)a.size())
#define FOR(i,j,k) for(int i=j;i<=k;i++)
#define REP(i,k,j) for(int i=k;i>=j;i--)
#define FORD(i,a) for(auto i:a)
#define rngdcl mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define random(l,r) ((l)+(rng()%(r-l+1)))
using namespace std;
const int nmax=5e4+69;
int n,m,k,q;
vector<pii> adj[nmax];
vector<pii> rev[nmax];
int suf[17][nmax][6],pfx[17][nmax][6];

void input()
{
    cin >> k >> n >> m >> q;
    FOR(i,1,m)
    {
        int u,v,w; cin >> u >> v >> w;
        u++; v++;
        adj[u].push_back({v,w});
        rev[v].push_back({u,w});
    }
}

pii pos(int x)
{
    return {(x-1)/k+1,(x-1)%k+1};
}	

void dnc(int l,int r,int lv)
{
    if(pos(l).fi==pos(r).fi || l>=r) return;
    int mid=(l+r)/2;
    
    //precase
    int sl=mid,sr=mid;
    while(pos(sl).fi==pos(mid).fi && sl>1) sl--;
    while(pos(sr).fi==pos(mid).fi && sr<n) sr++;
    FOR(i,sl,sr) suf[lv][i][pos(i).se]=0;
    FOR(i,sl,sr) pfx[lv][i][pos(i).se]=0;
    
    //build
    REP(u,sl,l)
    {
        FORD(i,adj[u])
        {
            FOR(j,1,k)
            {
                if(suf[lv][i.fi][j]!=L) suf[lv][u][j]=min(suf[lv][u][j],suf[lv][i.fi][j]+i.se);
            }
        }
    }
    FOR(u,sr,r)
    {
        FORD(i,rev[u])
        {
            FOR(j,1,k)
            {
                if(pfx[lv][i.fi][j]!=L) pfx[lv][u][j]=min(pfx[lv][u][j],pfx[lv][i.fi][j]+i.se);
            }
        }
    }
    
    //recursion
    dnc(l,mid-1,lv+1);
    dnc(mid+1,r,lv+1);
}

pii find(int l,int r,int lv,int lf,int rt)
{
    int mid=(l+r)/2;
    if(l<=lf && rt<=r && lf<=mid && mid<=rt) return {lv,mid};
    if(l<=lf && rt<=mid) return find(l,mid,lv+1,lf,rt);
    else return find(mid+1,r,lv+1,lf,rt);
}

void solve()
{
    //preprocess
    FOR(i,0,16) FOR(j,1,n) FOR(k,1,5)
    {
        suf[i][j][k]=L;
        pfx[i][j][k]=L;
    }
    dnc(1,n,1);
//    FOR(lv,1,4) {FOR(i,1,n) {FOR(j,1,k) cout << suf[lv][i][j] << ' '; cout << '\n';} cout << '\n';}
    
    //query
    while(q--)
    {
        int l,r; cin >> l >> r;
        l++; r++;
        pii save=find(1,n,1,l,r);
        int mid=save.se;
        int lv=save.fi;
        int ans=L;
        if(pos(l).fi+1==pos(r).fi)
        {
            FORD(i,adj[l]) if(i.fi==r) ans=i.se;
        }
        else
        {
            FOR(i,1,k) if(suf[lv][l][i]!=L && pfx[lv][r][i]!=L) ans=min(ans,suf[lv][l][i]+pfx[lv][r][i]);
        }
        if(ans==L) cout << -1 << '\n';
        else cout << ans << '\n';
    }
}

signed main()
{
    //freopen(".inp", "r", stdin);
    //freopen(".out", "w", stdout);
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    input();
    solve();
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 10
• Subtask 3: 0 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44