1072. Gas Station (30)

开始用FLOY求最短路径，奈何最后个测试点超时，只能再试试DIJ来求，然后过了
需要注意的地方：
首先加油站离最近房子的距离尽可能远，如果有不同解，选路径和最小的那个，还一样选序号最小的一个，当然加油站里所有房子的最小路径都不能超过给的数，代码中贴有FLOY解法和DIJ解法，当然FLOY是超时的

#include<iostream>#include<vector>#include<string>#define INF 0x3f3f3fusing namespace std;int N, M, K, D;bool flag;int add, v;int change_index(string str){    if (str[0] == 'G') return N-1+stoi(string(str, 1));    else return stoi(str) - 1;}string change_name(int i){    if (i < N) return to_string(i+1);    else return string("G") + to_string(i + 1 - N);}vector<vector<int>> arc;vector<int> Dis;vector<int> Tem;vector<bool> visited;bool DIJ(int index){    int num = 0;    visited[index] = true;    Dis[index] = 0;    for (int t = 0;t < M + N;t++)        if (arc[index][t] != INF)            Tem[t] = arc[index][t];    while (num != N)    {        int temp_min=INF,temp_v;        for (int t = 0;t < M + N;t++)            if (!visited[t] && Tem[t] < temp_min) { temp_min = Tem[t];temp_v = t; }        Dis[temp_v] = temp_min;        visited[temp_v] = true;        if (temp_v < N) {            num++;            add +=temp_min;            if (temp_min < v) v = temp_min;            if (temp_min > D) { flag = false;break; }        }        for (int t = 0;t < M + N;t++)            if (!visited[t] && Tem[t]>temp_min + arc[temp_v][t]) Tem[t] = temp_min + arc[temp_v][t];    }    return true;}int main(){    cin >> N >> M >> K >> D;    if (N == 0)    {        printf("No Solution\n");        exit(0);    }    arc.resize(M + N);    for (int t = 0;t < M + N;t++)    {        arc[t].assign(M + N, INF);        arc[t][t] = 0;    }    for (int t = 0;t < K;t++)    {        string a, b;        int c;        cin >> a >> b >> c;        arc[change_index(a)][change_index(b)] = arc[change_index(b)][change_index(a)]=c;    }    //for (int t = 0;t < N + M;t++)    //  for (int i = 0;i < M + N;i++)    //      for (int j = 0;j < M + N;j++)    //      {    //          if (arc[i][t] + arc[t][j] < arc[i][j])    //              arc[i][j] = arc[i][t] + arc[t][j];    //      }    int min=0, sum=0;    int resault=0;    for (int t = N;t < M + N;t++)    {        Dis.assign(M + N, 0);        Tem.assign(M + N, INF);        flag = true;        add = 0;        v = INF;        visited.assign(M + N, false);        DIJ(t);        //int add = 0,v=INF;        //for (int i = 0;i < N;i++)        //{        //  if (arc[t][i] > D) { flag = 0;break; }        //  add += arc[t][i];        //  if (arc[t][i] < v) v = arc[t][i];        //}        if (flag == false)continue;        else if(v>min||(v==min && add<sum)){ sum = add;min = v;resault = t; }    }    if (resault == 0) cout << "No Solution" << endl;    else printf("%s\n%.1lf %.1lf\n", change_name(resault).c_str(), double(min), double(sum) / N);}