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Dijkstra.cpp
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Dijkstra.cpp
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#include <iostream>
#include <vector>
#include <queue>
#pragma warning(disable:4996)
using namespace std;
struct Cmp
{
bool operator()(const pair<int, int> & lth, const pair<int, int> & rth)
{
return lth.first > rth.first;
}
};
class Graph
{
public:
Graph(int nv) :m_v(nv), m_vec(nv, vector<int>(nv, 0))
{
}
void AddEdge(int from, int to, int weight)
{
m_vec[from][to] = weight;
m_vec[to][from] = weight;
}
void Dijkstra(int src)
{
// weight, v
priority_queue<pair<int, int>, vector<pair<int, int>>, Cmp> que;
vector<int> dist(m_v, INT_MAX);
dist[src] = 0;
que.push(make_pair(0, src));
while (!que.empty())
{
pair<int, int> top = que.top();
que.pop();
int from = top.second;
// ignore the old value
if (dist[from] < top.first)
{
continue;
}
for (int to = 0; to < m_v; ++to)
{
if (0 != m_vec[from][to] && dist[from] + m_vec[from][to] < dist[to])
{
dist[to] = dist[from] + m_vec[from][to];
que.push(make_pair(dist[to], to));
}
}
}
Print(dist);
}
void Print(const vector<int> & dist)
{
for (int i = 0; i < m_v; ++i)
{
cout << dist[i];
if (i + 1 == m_v)
{
cout << endl;
}
else
{
cout << " ";
}
}
}
private:
int m_v;
vector<vector<int>> m_vec;
};
int main()
{
Graph g(9);
g.AddEdge(0, 1, 4);
g.AddEdge(0, 7, 8);
g.AddEdge(1, 2, 8);
g.AddEdge(1, 7, 11);
g.AddEdge(2, 3, 7);
g.AddEdge(2, 8, 2);
g.AddEdge(2, 5, 4);
g.AddEdge(3, 4, 9);
g.AddEdge(3, 5, 14);
g.AddEdge(4, 5, 10);
g.AddEdge(5, 6, 2);
g.AddEdge(6, 7, 1);
g.AddEdge(6, 8, 6);
g.AddEdge(7, 8, 7);
g.Dijkstra(0);
}