Submission #935026

#	Time	Username	Problem	Language	Result	Execution time	Memory
935026		Hanksburger	Toll (BOI17_toll)	C++17	8 / 100	427 ms	123636 KiB

toll

#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > adj[50005], rev[50005];
map<pair<int, int>, int> mp;
int dist[50005];
void recur(int l, int r, int c)
{
    int mid=(l+r)/2;
    for (int i=c*mid; i<c*(mid+1); i++)
    {
        for (int j=c*l; j<c*(r+1); j++)
            dist[j]=1e9;
        dist[i]=0;
        for (int j=c*mid-1; j>=c*l; j--)
        {
            for (int k=0; k<adj[j].size(); k++)
                dist[j]=min(dist[j], dist[adj[j][k].first]+adj[j][k].second);
            mp[{j, i}]=dist[j];
        }
        for (int j=c*(mid+1); j<c*(r+1); j++)
        {
            for (int k=0; k<rev[j].size(); k++)
                dist[j]=min(dist[j], dist[rev[j][k].first]+rev[j][k].second);
            mp[{i, j}]=dist[j];
        }
    }
    if (l+2<=mid)
        recur(l, mid-1, c);
    if (mid+2<=r)
        recur(mid+1, r, c);
}
int dfs(int l, int r, int u, int v)
{
    int mid=(l+r)/2;
    if (v<mid)
        return dfs(l, mid-1, u, v);
    if (u>mid)
        return dfs(mid+1, r, u, v);
    return mid;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int c, n, m, q;
    cin >> c >> n >> m >> q;
    for (int i=0; i<m; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
        rev[v].push_back({u, w});
    }
    recur(0, (n-1)/c, c);
    for (int i=0; i<q; i++)
    {
        int u, v;
        cin >> u >> v;
        int x=dfs(0, (n-1)/c, u/c, v/c);
        if (u/c==x && v/c==x)
            cout << -1 << '\n';
        else if (u/c==x || v/c==x)
            cout << mp[{u, v}] << '\n';
        else
        {
            int ans=1e9;
            for (int j=c*x; j<c*(x+1); j++)
                ans=min(ans, mp[{u, j}]+mp[{j, v}]);
            cout << (ans==1e9?-1:ans) << '\n';
        }
    }
}

Compilation message (stderr)

toll.cpp: In function 'void recur(int, int, int)':
toll.cpp:16:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |             for (int k=0; k<adj[j].size(); k++)
      |                           ~^~~~~~~~~~~~~~
toll.cpp:22:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |             for (int k=0; k<rev[j].size(); k++)
      |                           ~^~~~~~~~~~~~~~

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