用C++实现代码：1、实现图的深度优先遍历和广度优先遍历 2、最短路径算法。最短路径算法的实现，编写算法获得带权有向图中从源点到其他各点的最短路径。

下面是用C++实现图的深度优先遍历和广度优先遍历的代码：

#include <iostream>
#include <vector>
#include <queue>
#include <stack>

using namespace std;

class Graph {
public:
    Graph(int n) {
        this->n = n;
        adj.resize(n);
    }

    void addEdge(int u, int v) {
        adj[u].push_back(v);
    }

    void dfs(int s) {
        vector<bool> visited(n, false);
        dfsUtil(s, visited);
    }

    void bfs(int s) {
        vector<bool> visited(n, false);
        queue<int> q;
        visited[s] = true;
        q.push(s);

        while (!q.empty()) {
            int u = q.front();
            q.pop();
            cout << u << " ";

            for (int i = 0; i < adj[u].size(); i++) {
                int v = adj[u][i];
                if (!visited[v]) {
                    visited[v] = true;
                    q.push(v);
                }
            }
        }
    }

private:
    int n;
    vector<vector<int>> adj;

    void dfsUtil(int u, vector<bool>& visited) {
        visited[u] = true;
        cout << u << " ";

        for (int i = 0; i < adj[u].size(); i++) {
            int v = adj[u][i];
            if (!visited[v]) {
                dfsUtil(v, visited);
            }
        }
    }
};

int main() {
    Graph g(4);
    g.addEdge(0, 1);
    g.addEdge(0, 2);
    g.addEdge(1, 2);
    g.addEdge(2, 0);
    g.addEdge(2, 3);
    g.addEdge(3, 3);

    cout << "DFS starting from vertex 2: ";
    g.dfs(2);
    cout << endl;

    cout << "BFS starting from vertex 2: ";
    g.bfs(2);
    cout << endl;

    return 0;
}

下面是用C++实现最短路径算法的代码：

#include <iostream>
#include <vector>
#include <queue>
#include <limits.h>

using namespace std;

#define INF INT_MAX

class Graph {
public:
    Graph(int n) {
        this->n = n;
        adj.resize(n);
    }

    void addEdge(int u, int v, int w) {
        adj[u].push_back(make_pair(v, w));
    }

    void shortestPath(int s) {
        vector<int> dist(n, INF);
        dist[s] = 0;

        priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
        pq.push(make_pair(0, s));

        while (!pq.empty()) {
            int u = pq.top().second;
            pq.pop();

            for (int i = 0; i < adj[u].size(); i++) {
                int v = adj[u][i].first;
                int w = adj[u][i].second;

                if (dist[v] > dist[u] + w) {
                    dist[v] = dist[u] + w;
                    pq.push(make_pair(dist[v], v));
                }
            }
        }

        cout << "Shortest distances from source vertex: " << endl;
        for (int i = 0; i < n; i++) {
            cout << s << " -> " << i << " = " << dist[i] << endl;
        }
    }

private:
    int n;
    vector<vector<pair<int, int>>> adj;
};

int main() {
    Graph g(5);
    g.addEdge(0, 1, 10);
    g.addEdge(0, 4, 5);
    g.addEdge(1, 2, 1);
    g.addEdge(1, 4, 2);
    g.addEdge(2, 3, 4);
    g.addEdge(3, 2, 6);
    g.addEdge(3, 0, 7);
    g.addEdge(4, 1, 3);
    g.addEdge(4, 2, 9);
    g.addEdge(4, 3, 2);

    g.shortestPath(0);

    return 0;
}