一.图的遍历

#include<iostream>
#include<queue>
#include<vector>
using namespace std;
int n, m;  //行数和列数
const int maxn = 100;
char g[maxn][maxn];  //图
bool vis[maxn][maxn];  //访问标记数组,false表示点没有被访问过
int disx[4] = { 0,0,1,-1 };   //四个
int disy[4] = { 1,-1,0,0 };   //方向
int dx, dy;   //起点位置
int counter;  //黑瓷砖的数目
bool flag = false; //判断是否有起点
struct node {
    int x, y;
}p[maxn];
queue<node> que;
vector<node> vec;
void graph(int n, int m) {
    cout << "请输入行数和列数 ：";
    cin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            cin >> g[i][j];
        }
    }
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            if (g[i][j] == '@') {
                dx = i; dy = j;
                flag = true;
                break;
            }
        }
        if (flag == true) break;
    }
    if (flag) {
        cout << "起始点的坐标是";
        printf("( %d , %d )\n\n", dx, dy);
    }
    else cout << "没有起点" << endl;
}
void bfs() {
    vec.clear();
    que.empty();
    memset(vis, false, sizeof vis);
    graph(n, m);
    if (!flag) {
        counter = 0;
        cout << "黑瓷砖的数目是" << counter << endl;
    }
    else {
        counter = 1;
        node point;
        point.x = dx, point.y = dy;
        que.push(point);
        vis[point.x][point.y] = true;
        vec.push_back(point);
        while (!que.empty()) {
            node temp = que.front();
            node next;
            que.pop();
            for (int i = 0; i < 4; ++i) {
                int x = temp.x + disx[i];
                int y = temp.y + disy[i];
                next.x = x; next.y = y;
                if (g[next.x][next.y] == 'b'&&vis[next.x][next.y] == false) {
                    vis[next.x][next.y] = true;
                    que.push(next); ++counter;
                    vec.push_back(next);
                }
            }
        }
        cout << "黑瓷砖的数目是" << counter << endl;
        cout << endl;
        int number = 0;
        cout << "且到达每个黑瓷砖的顺序是 ：" << endl;
        for (int i = 0; i < vec.size(); ++i) {
            if (i != vec.size() - 1) {
                ++number;
                printf("( %d , %d)", vec[i].x, vec[i].y);
                cout << " -> ";
                if (number % 5 == 0) cout << endl;
            }
            else printf("( %d , %d)\n", vec[i].x, vec[i].y);
        }
    }
}
int main() {
    bfs();
    return 0;
}

糟糕的上机，prim似乎有bug

二.求无向连通图的生成树

#pragma once
#include<algorithm>
#include <fstream>
#include<iostream>
using namespace std;
const int inf = 1000000000;
int p[100];
int maze[100][100];
template<class T>
struct Edge
{
    int u, v;
    int net;
    T key;
    Edge() :u(-1), v(-1), key(0) {}
};
template<class T>
class MST {
protected:
    Edge<T>*edge;
    int maxSize, e;
    int head[100];
public:MST(int sz = 100) :maxSize(sz), e(0) {
    edge = new Edge<T>[sz];
    memset(head, -1, sizeof(head));
}
       void addedge(Edge<T>& item);
       void establish();
       int Kruskal();
       int Prim(int n);
};
template<class T>
void MST<T>::addedge(Edge<T>& item)
{
    int frm = item.u, to = item.v, w = item.key;
    edge[e].u = frm;
    edge[e].v = to;
    edge[e].key = w;
    edge[e].net = head[frm];
    head[frm] = e++;
    edge[e].u = to;
    edge[e].v = frm;
    edge[e].key = w;
    edge[e].net = head[to];
    head[to] = e++;
}
template<class T>
void MST<T>::establish()
{
    for (int i = 0; i < 100; i++)
        for (int j = 0; j< 100; j++)
            if (i == j)maze[i][j] = 0;
            else maze[i][j] = inf;
    int u, v, w;
    Edge<int> temp;
    while (cin >> u >> v >> w) {
        if (u == 0 && v == 0 && w == 0)break;
        temp.u = u, temp.v = v, temp.key = w;
        maze[u][v] = maze[v][u] = w;
        addedge(temp);
    }
    return;
}
bool cmp(Edge<int> a, Edge<int> b)
{
    return a.key < b.key;
}
int find(int x)
{
    return p[x] == x ? x : p[x] = find(p[x]);
}
template<class T>
int MST<T>::Kruskal()
{

    ofstream outfile;
    
    outfile.open("outdata.txt");
    outfile << "Kruskal计算如下:\n";
    int ans = 0;
    for (int i = 0; i < 50; i++)p[i] = i;
    sort(edge, edge + e, cmp);
    for (int i = 0; i < e; i++) {
        int x = find(edge[i].u);
        int y = find(edge[i].v);
        if (x != y) { ans += edge[i].key;
    //  cout << edge[i].u << " " << edge[i].v << endl;
        outfile << edge[i].u << "    " << edge[i].v<<"     权值：  " << edge[i].key << endl;

              p[x] = y; }
    }
    outfile << "最小生成树中长度：   " << ans << endl;
    outfile.close();//关闭文件，保存文件。
    return ans;
}
Edge<int> dis[100];
int path[100];
template<class T>
int MST<T>::Prim(int n)
{
    
    bool vis[100];
    ofstream outfile;
    outfile.open("outdata.txt", ios::binary | ios::app | ios::in | ios::out);
    outfile << "Prim计算如下:\n\n\n";
    //int dis[100];
    for (int i = 0; i < 100; i++)
        dis[i].key = inf;
        memset(vis, 0, sizeof(vis));
        int ans = 0;
        dis[3].key = 0;
        while (1)
        {
            int k = 0;
            for (int j = 1; j <= n; j++)
            {
                if (!vis[j] && dis[j].key<dis[k].key)      //这一步找未收录顶点中dist值最小的
                    k = j;            
            }
            if (!k) break;
            vis[k] = 1;                        
            ans += dis[k].key;
            if (dis[k].u > 0)
                outfile <<"    "<<dis[k].u << "    " << dis[k].v << "     权值" << dis[k].key << "\n" << endl;
            for (int j = 1; j <= n; j++)
            {
                if (dis[j].key>maze[k][j])
                {
                    dis[j].key = maze[k][j];
                    dis[j].u = k;
                    dis[j].v = j;
                    path[j] = k;
                }
            }
        }
        outfile << "总长度    " << ans << endl;
        outfile.close();//关闭文件，保存文件。
        
        return ans;
}

#include<iostream>
#include"graph.h"
using namespace std;
int main()
{
    MST<int> m;
    int n;
    cin >> n;
    m.establish();
    m.Kruskal();
    m.Prim(n);
    getchar();
    return 0;
}