【基础】图论基础 2017/04/20

 用临接链表表示一张图， 可以给图加边， 可以bfs

#include <iostream>
#include <list>
#include <vector>
#include <queue>

using namespace std;

void createGraph(const int& N) {
    return;
}

void addEdge(const int fromNode, const int endNode, vector<list<int>>& graph) {
    graph[fromNode].push_back(endNode);
}


void bfs(vector<list<int>>& graph, int start) {
    const int N = graph.size();
    vector<int> ans;
    queue<int> q;
    vector<bool> visit(N, false);
    q.push(start);
    visit[start] = true;
    while(!q.empty()) {
        int cur = q.front();
        q.pop();
        ans.push_back(cur);
        for (auto iter = graph[cur].begin(); iter != graph[cur].end(); ++iter) {
            if (!visit[*iter]) {
                q.push(*iter);
                visit[*iter] = true;
            }
        }
    }
    for (auto ele : ans) {
        cout << ele << " ";
    }
}

void print_graph(vector<list<int>>& graph) {
    const int N = graph.size();
    for (auto i = 0; i < N; ++i) {
        const int M = graph[i].size();
        int j = 0;
        for (auto iter = graph[i].begin(); iter != graph[i].end(); ++iter, ++j) {
            cout << *iter ;
            if (j == M - 1) {
                cout << endl;
            } else {
                cout << " -> ";
            }
        }
    }
    return;
}


int main() {

    const int N = 4;
    vector<list<int>> graph(N, list<int>());
    for (auto i = 0; i < N; ++i) {
        graph[i].push_back(i);
    }
    addEdge(0, 1, graph);
    addEdge(0, 2, graph);
    addEdge(1, 2, graph);
    addEdge(2, 0, graph);
    addEdge(2, 3, graph);
    addEdge(3, 3, graph);

    print_graph(graph);

    bfs(graph, 1);

    return 0;
}

 dfs 基础练习

http://practice.geeksforgeeks.org/problems/depth-first-traversal-for-a-graph/1