CareerCup-4.2

Given a directed graph, design an algorithm to find out whether there is a route between two nodes.

开始想用Dijkstra算法，后来发现根本不需要最短只求连通性。回头还得回忆下Dijkstra，写起来有点生疏了。 

#include <iostream>
#include <stack>
using namespace std;
#define Data int
class Graph
{
public:
    Graph(int size):mSize(size)
    {
        data = new Data*[size];
        for(int i=0; i<size; i++)
        {
            data[i] = new Data[size];
            for(int j=0; j<size; j++)
            {
                data[i][j] = 0;
            }
        }
    };
    void addLink(int src, int dst, int weight=1)
    {
        data[src][dst] = weight;
    };
    bool isReached(int src, int dst)
    {
        if(src == dst) return true;
        bool reached[mSize];
        for(int i=0; i<mSize; i++)
            reached[i] = false;
        stack<Data> stack;
        stack.push(src);
        reached[src] = true;
        while(true)
        {
            Data d = stack.top();
            cout<<"Reach: "<<d<<endl;
            if(d == dst)
                return true;
            stack.pop();
            for(int i=0; i<mSize; i++)
            {
                if(data[d][i] > 0 && !reached[i])
                    stack.push(i);
            };
            if(stack.empty()) break;
        };
        return false;
    };
private:
    int mSize;
    Data** data;
};

int main()
{
    Graph graph(4);
    graph.addLink(0, 3);
    graph.addLink(3, 2);
    cout<<boolalpha<<graph.isReached(0, 1)<<endl;
    system("pause");
}