Submission #732118

#	Time	Username	Problem	Language	Result	Execution time	Memory
732118		Trunkty	Toll (BOI17_toll)	C++14	100 / 100	1367 ms	35212 KiB

toll

#include <bits/extc++.h>
using namespace std;
typedef long long ll;
#define int ll

int k,n,m,q;
vector<vector<int>> roads[50005],rev[50005],query[200005];
int best[50005],ans[10005];
bool check[50005];

void update(int node, int l, int r, int a, int b, int ind){
    int mid = (l+r)/2;
    if(a/k<=mid and mid<=b/k){
        query[node].push_back({a,b,ind});
    }
    else if(b/k<=mid){
        update(node*2,l,mid,a,b,ind);
    }
    else{
        update(node*2+1,mid+1,r,a,b,ind);
    }
}

void walk(int node, int l, int r){
    int mid = (l+r)/2;
    if(l!=r){
        walk(node*2,l,mid);
        walk(node*2+1,mid+1,r);
    }
    int lef=l*k,rit=r*k+k-1;
    for(int i=0;i<=k-1;i++){
        for(int j=lef;j<=rit;j++){
            best[j] = 2e9;
            check[j] = false;
        }
        priority_queue<vector<int>,vector<vector<int>>,greater<vector<int>>> pq;
        best[mid*k+i] = 0;
        pq.push({0,mid*k+i});
        while(pq.size()>0){
            while(pq.size()>0 and check[pq.top()[1]]){
                pq.pop();
            }
            if(pq.size()==0){
                break;
            }
            int x = pq.top()[1];
            pq.pop();
            check[x] = true;
            for(vector<int> j:roads[x]){
                if(j[0]<=rit and best[x]+j[1]<best[j[0]]){
                    best[j[0]] = best[x]+j[1];
                    pq.push({best[j[0]],j[0]});
                }
            }
        }
        pq.push({0,mid*k+i});
        check[mid*k+i] = false;
        while(pq.size()>0){
            while(pq.size()>0 and check[pq.top()[1]]){
                pq.pop();
            }
            if(pq.size()==0){
                break;
            }
            int x = pq.top()[1];
            pq.pop();
            check[x] = true;
            for(vector<int> j:rev[x]){
                if(j[0]>=lef and best[x]+j[1]<best[j[0]]){
                    best[j[0]] = best[x]+j[1];
                    pq.push({best[j[0]],j[0]});
                }
            }
        }
        for(vector<int> j:query[node]){
            ans[j[2]] = min(ans[j[2]],best[j[0]]+best[j[1]]);
        }
    }
}

signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
    cin >> k >> n >> m >> q;
    for(int i=1;i<=m;i++){
        int a,b,c;
        cin >> a >> b >> c;
        roads[a].push_back({b,c});
        rev[b].push_back({a,c});
    }
    for(int i=1;i<=q;i++){
        int a,b;
        cin >> a >> b;
        update(1,0,n/k,a,b,i);
        ans[i] = 2e9;
    }
    walk(1,0,n/k);
    for(int i=1;i<=q;i++){
        if(ans[i]==2e9){
            cout << -1 << "\n";
        }
        else{
            cout << ans[i] << "\n";
        }
    }
	return 0;
}

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