PAT 1087

又是最短路，陈越姥姥好像很喜欢最短路... 这道题之后还得再写一遍，最短路一定要熟悉

碰到一个坑，就是在加最短路的时候，不是++，而是要把前面的最短路加进来... 

#include <vector>
#include <string>
#include <iostream>
#include <map>
#include <fstream>

//#define OJ

#ifdef OJ
#define fin cin
#endif

using namespace std;

class city{
public:
    int happiness;
    string name;
    
    vector<int> adj;
    vector<int> cost;
};

vector<city> cities;
map<string, int> city_idx;
map<int, string> city_name;

void dij(){
    int total = cities.size();
    int MAX = 0x7fffffff;

    vector<bool> visited(total, false);
    vector<int> dij_dist(total, MAX);
    vector<int> dij_happiness(total, 0);
    vector<int> prev(total, -1);
    vector<int> dij_cnt(total, MAX);
    vector<int> dij_least_cnt(total, 0);

    int target_idx = city_idx["ROM"];

    dij_dist[0] = 0;
    dij_cnt[0] = 0;
    dij_least_cnt[0] = 1;

    while (true){
        int least_dist = MAX;
        int least_idx = -1;

        for (int i = 0; i < total; i++){
            if (!visited[i] && least_dist > dij_dist[i]){
                least_idx = i;
                least_dist = dij_dist[i];
            }
        }

        if (least_idx == -1)
            break;
        if (least_idx == target_idx) // ?
            break;

        visited[least_idx] = true;
        vector<int> &adj = cities[least_idx].adj;
        vector<int> &cost = cities[least_idx].cost;
        for (int i = 0; i < adj.size(); i++){
            int cur_idx = adj[i];
            if (visited[cur_idx])
                continue;
            if (least_dist + cost[i] < dij_dist[cur_idx]){
                dij_dist[cur_idx] = least_dist + cost[i];
                prev[cur_idx] = least_idx;
                dij_cnt[cur_idx] = dij_cnt[least_idx] + 1;
                dij_happiness[cur_idx] = dij_happiness[least_idx] + cities[cur_idx].happiness;
                dij_least_cnt[cur_idx] = dij_least_cnt[least_idx];
            }
            else if (least_dist + cost[i] == dij_dist[cur_idx]){
                dij_least_cnt[cur_idx] += dij_least_cnt[least_idx];

                if (dij_happiness[least_idx] + cities[cur_idx].happiness > dij_happiness[cur_idx]){
                    prev[cur_idx] = least_idx;
                    dij_cnt[cur_idx] = dij_cnt[least_idx] + 1;
                    dij_happiness[cur_idx] = dij_happiness[least_idx] + cities[cur_idx].happiness;
                }
                else if (dij_happiness[least_idx] + cities[cur_idx].happiness == dij_happiness[cur_idx]){
                    if (dij_cnt[least_idx] + 1 < dij_cnt[cur_idx]){
                        prev[cur_idx] = least_idx;
                        dij_cnt[cur_idx] = dij_cnt[least_idx] + 1;
                    }
                }
            }
        }
    }

    int idx = target_idx;
    cout << dij_least_cnt[target_idx] << " " << dij_dist[target_idx] << " " << dij_happiness[target_idx] << " " << (int)(dij_happiness[target_idx] / dij_cnt[target_idx]) << endl;
    
    vector<int> res;
    
    while (idx != 0){
        res.push_back(idx);
        idx = prev[idx];
    }
    cout << city_name[0];
    for (int i = res.size() - 1; i >= 0; i--)
        cout << "->" << city_name[res[i]];
    cout << endl;
}

int main(){
#ifndef OJ
    ifstream fin;
    fin.open("in.data");
#endif


    int N, K;
    fin >> N >> K;

    string name;
    fin >> name;
    city_idx[name] = 0;
    city_name[0] = name;

    city c;
    c.name = name;
    c.happiness = 0;

    cities.push_back(c);

    for (int i = 1; i < N; i++){
        fin >> c.name;
        fin >> c.happiness;

        cities.push_back(c);

        city_name[i] = c.name;
        city_idx[c.name] = i;
    }

    for (int i = 0; i < K; i++){
        int c1, c2, cost;

        fin >> name;
        c1 = city_idx[name];

        fin >> name;
        c2 = city_idx[name];

        fin >> cost;

        cities[c1].adj.push_back(c2);
        cities[c1].cost.push_back(cost);
        cities[c2].adj.push_back(c1);
        cities[c2].cost.push_back(cost);
    }

    dij();

    return 0;
}