無權圖的單源最短路算法

思路是廣度優先搜尋，每次記錄路徑和距離

#include<stdio.h>
#include<stdlib.h>
#include <string.h>
#include <string>
#include <iostream>
#include <stack>
#include <math.h>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <map>
#include <string>
#include <stdlib.h>
#include <vector>
#include <queue>
#include <functional>
using namespace std;
vector <int> graph[8];//鄰接表
int dist[8];//最短距離
int path[8];//路徑
queue<int> q;
stack<int> s;
void unweighted()
{
    q.push(1);
    dist[1] = 0;
    path[1] = 0;
    while(!q.empty())
    {
        int now = q.front();
        q.pop();
        for(int i=0; i<graph[now].size(); i++)
        {
            if(dist[graph[now][i]]==-1)
        {
            dist[graph[now][i]] = dist[now]+1;
            path[graph[now][i]] = now;
                q.push(graph[now][i]);
        }

        }
    }
}
int main()
{
    graph[1].push_back(2);
    graph[1].push_back(4);
    graph[2].push_back(4);
    graph[2].push_back(5);
    graph[3].push_back(1);
    graph[3].push_back(6);
    graph[4].push_back(3);
    graph[4].push_back(5);
    graph[4].push_back(6);
    graph[4].push_back(7);
    graph[5].push_back(7);
    graph[7].push_back(6);
    memset(dist,-1,sizeof(dist));
    memset(path,0,sizeof(path));
    unweighted();
    int i=6;
    while(i!=0)
    {
        s.push(i);
        i = path[i];
    }
    while(!s.empty())
    {
        cout<<s.top()<<"->";
        s.pop();
    }
    cout<<endl;
    for(int i=1;i<=7;i++)
        cout<<dist[i]<<endl;
    return 0;

}