1018. Public Bike Management (30)

有个坑：不能把后面多出来的自行车补到前面缺的地方，可用DFS或DIJ
DFS方法

#include<iostream>#include<vector>#define INF 0x3f3f3f#define MAX_bike 102#define MAX_V 502using namespace std;int C, N, sp, M;int t_min=INF;int send=0, back=0;vector<int> path;//输出变量int temp_send=0, temp_back=0,temp_min=0;vector<int> temp_path;//临时变量int arc[MAX_V][MAX_V] = {0};//邻接矩阵int bike[MAX_V];//顶点自行车数量bool visited[MAX_V];//bfs中是否被访问void intipath()//对路径求temp_back和temp_send    {        int temp;        temp = 0, temp_send = 0;        for (auto x : temp_path)        {            if (bike[x] + temp < 0)             {                temp_send += -(bike[x] + temp);temp = 0;            }            else temp = bike[x] + temp;        }        temp_back = temp;    }void bfs(int index)//bfs{    if (temp_min > t_min) { return; }//剪枝    if (index == sp)    {        intipath();        if (temp_min < t_min || (temp_min==t_min && temp_send<send)||(temp_min==t_min && temp_send==send && temp_back<back) )        {            t_min = temp_min;send = temp_send;back = temp_back;path = temp_path;        }        return;    }    for (int t = 1;t <= N;t++)    {        if (visited[t] == false && arc[index][t] != 0)        {            visited[t] = true;            temp_path.push_back(t);            temp_min += arc[index][t];            bfs(t);            visited[t] = false;//回溯            temp_path.pop_back();            temp_min -= arc[index][t];        }    }}int main(){    cin >> C >> N >> sp >> M;    bike[0] = 0;    for (int t = 1;t <= N;t++)    {        cin >> bike[t];        bike[t] -= C / 2;    }    for (int t = 0;t < M;t++)    {        int i, j,k;        cin >> i >> j >> k;        arc[i][j] = arc[j][i]=k;    }    visited[0] = true;    bfs(0);    cout << send << " 0";    for (auto it = path.begin();it != path.end();it++)        cout << "->" << *it;    cout << " " << back << endl;    return 0;}

DIJ方法：

#include<iostream>#include<vector>#define MAX_V 502#define MAX_bike 102#define INF 0x3f3f3f//vector保存的路径不包括0using namespace std;vector<vector<int>> temp_path[MAX_V];//临时路径，求所有最短路径解int arc[MAX_V][MAX_V] = {0};//邻接矩阵int bike[MAX_V];//顶点自行车数量int D[MAX_V] = {0};//最短路径int temp_D[MAX_V];//DIJ临时变量int C, N, sp, M;int temp_send, temp_back;vector<int> path;int send=INF, back;//最后要输出的void DIJ(){    for (int t = 1;t <= N;t++)        if (arc[0][t] != 0) temp_D[t] = arc[0][t];    while (D[sp] == 0)    {           int temp_min=INF, temp_v;        for (int t = 1;t <= N;t++)            if (D[t]==0 && temp_D[t] < temp_min)            {                temp_min = temp_D[t];                temp_v = t;            }        D[temp_v] = temp_min;        for (auto &x : temp_path[temp_v])            x.push_back(temp_v);        for (int t = 1;t <= N;t++)//更新temp_D        {            if (D[t] == 0 && arc[temp_v][t]!=0)            {                if (temp_min + arc[temp_v][t] < temp_D[t])                {                    temp_D[t] = temp_min + arc[temp_v][t];                    temp_path[t] = temp_path[temp_v];                }                else if (temp_min + arc[temp_v][t] == temp_D[t])                {                    temp_path[t].insert(temp_path[t].end(), temp_path[temp_v].begin(), temp_path[temp_v].end());                }            }        }    }}void intipath(vector<int> p){    temp_send = 0;    int temp = 0;    for (auto x : p)    {        if (temp + bike[x] < 0)        {            temp_send += -(temp + bike[x]);            temp = 0;        }        else            temp = temp + bike[x];    }    temp_back = temp;}int main(){    cin >> C >> N >> sp >> M;    vector<int> vec;    for (int t = 1;t <= N;t++)    {        cin >> bike[t];        bike[t] -= C / 2;        temp_D[t] = INF;//初始化        temp_path[t].push_back(vec);    }    for (int t = 0;t < M;t++)    {        int i, j,k;        cin >> i >> j >> k;        arc[i][j] = arc[j][i] = k;    }    DIJ();    for (auto x : temp_path[sp])    {        intipath(x);        if (temp_send < send || (temp_send == send && temp_back < back))        {            path = x;            send = temp_send;            back = temp_back;        }    }    cout << send << " 0";    for (auto x : path)        cout << "->" << x;    cout << " " << back << endl;}