Submission #982377

#	Time	Username	Problem	Language	Result	Execution time	Memory
982377		simona1230	Swapping Cities (APIO20_swap)	C++17	30 / 100	1764 ms	51936 KiB

swap

#include "swap.h"
#include <bits/stdc++.h>
using namespace std;

int maxx,minn,maxw;
int n,m,x,y;
vector<int> v[100001],w[100001],num[100001];
pair<int,int> p[100001];
bool sec=1;

struct edge
{
    int x,y,d;
    edge() {}
    edge(int _x,int _y,int _d)
    {
        x=_x;
        y=_y;
        d=_d;
    }

    bool operator<(const edge&e)const
    {
        return e.d<d;
    }
};

void init(int N, int M,std::vector<int> U, std::vector<int> V, std::vector<int> W)
{
    minn=N;
    n=N;
    m=M;
    for(int i=0; i<m; i++)
    {
        if(U[i]!=0)sec=0;
        maxw=max(maxw,W[i]);
        v[U[i]].push_back(V[i]);
        v[V[i]].push_back(U[i]);
        w[U[i]].push_back(W[i]);
        w[V[i]].push_back(W[i]);
        num[U[i]].push_back(i);
        num[V[i]].push_back(i);
        maxx=max(maxx,(int)v[U[i]].size());
        maxx=max(maxx,(int)v[V[i]].size());
        p[i]= {W[i],V[i]};
    }
    sort(p,p+m);

    for(int i=0; i<n; i++)
    {
        minn=min(minn,(int)v[i].size());
    }
}

int d[1024][1024];
void dijkstra()
{
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {
            d[i][j]=1e9+1;
        }
    }

    priority_queue<edge> q;

    q.push({x,y,0});
    d[x][y]=0;

    while(q.size())
    {
        edge e=q.top();
        q.pop();
        //cout<<e.x<<" "<<e.y<<" "<<e.d<<endl;

        if(d[e.x][e.y]>=e.d)
        {
            for(int i=0; i<v[e.x].size(); i++)
            {
                int nb1=v[e.x][i];
                //cout<<nb1<<"-"<<e.y<<endl;
                if(nb1!=e.y)
                {
                    if(d[nb1][e.y]>max(d[e.x][e.y],w[e.x][i]))
                    {
                        //cout<<"in"<<endl;
                        d[nb1][e.y]=max(d[e.x][e.y],w[e.x][i]);
                        q.push({nb1,e.y,d[nb1][e.y]});
                    }
                }
            }

            for(int j=0; j<v[e.y].size(); j++)
            {
                int nb2=v[e.y][j];
                if(nb2!=e.x)
                {
                    if(d[e.x][nb2]>max(d[e.x][e.y],w[e.y][j]))
                    {
                        d[e.x][nb2]=max(d[e.x][e.y],w[e.y][j]);
                        q.push({e.x,nb2,d[e.x][nb2]});
                    }
                }
            }
        }

    }
}

int getMinimumFuelCapacity(int X, int Y)
{
    x=X;
    y=Y;
    if(maxx<=2)
    {
        if(minn==1)return -1;
        return maxw;
    }

    if(sec)
    {
        if(x==0||y==0)
        {
            if(x>y)swap(x,y);
            int i1=0,i2=1;
            if(p[0].second==y)i1=2;
            if(p[1].second==y)i2=2;
            int ans=max(p[i1].first,p[i2].first);
            ans=max(ans,w[y][0]);
            return ans;
        }
        int ans=p[0].first;
        if(p[0].second==x||p[0].second==y)ans=p[1].first;
        if(p[1].second==x||p[1].second==y)ans=p[2].first;
        ans=max(ans,w[x][0]);
        ans=max(ans,w[y][0]);
        return ans;
    }

    dijkstra();
    int ans=d[y][x];
    if(ans==1e9+1)ans=-1;
    return ans;
}
/*
5 4
0 1 1
0 2 2
0 3 3
0 4 4
4
0 1
0 2
0 3
0 4

*/

Compilation message (stderr)

swap.cpp: In function 'void dijkstra()':
swap.cpp:79:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |             for(int i=0; i<v[e.x].size(); i++)
      |                          ~^~~~~~~~~~~~~~
swap.cpp:94:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   94 |             for(int j=0; j<v[e.y].size(); j++)
      |                          ~^~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27