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Merge pull request #998 from fhlasek/prim

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fix: linter for prim.
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David Leal 2020-08-10 12:34:00 -05:00 committed by GitHub
commit 250c0c4d0a
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1 changed files with 24 additions and 25 deletions
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graph/prim.cpp
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@ -3,56 +3,55 @@
#include <queue>
#include <vector>
const int MAX = 1e4 + 5;
typedef std::pair<int, int> PII;
using PII = std::pair<int, int>;
bool marked[MAX];
std::vector<PII> adj[MAX];
int prim(int x) {
int prim(int x, const std::vector< std::vector<PII> > &graph) {
// priority queue to maintain edges with respect to weights
std::priority_queue<PII, std::vector<PII>, std::greater<PII> > Q;
int y;
int minimumCost = 0;
PII p;
std::vector<bool> marked(graph.size(), false);
int minimum_cost = 0;
Q.push(std::make_pair(0, x));
while (!Q.empty()) {
// Select the edge with minimum weight
p = Q.top();
PII p = Q.top();
Q.pop();
x = p.second;
// Checking for cycle
if (marked[x] == true)
if (marked[x] == true) {
continue;
minimumCost += p.first;
}
minimum_cost += p.first;
marked[x] = true;
for (int i = 0; i < adj[x].size(); ++i) {
y = adj[x][i].second;
if (marked[y] == false)
Q.push(adj[x][i]);
for (const PII &neighbor : graph[x]) {
int y = neighbor.second;
if (marked[y] == false) {
Q.push(neighbor);
}
}
return minimumCost;
}
return minimum_cost;
}
int main() {
int nodes, edges, x, y;
int weight, minimumCost;
int nodes = 0, edges = 0;
std::cin >> nodes >> edges; // number of nodes & edges in graph
if (nodes == 0 || edges == 0)
if (nodes == 0 || edges == 0) {
return 0;
}
std::vector< std::vector<PII> > graph(nodes);
// Edges with their nodes & weight
for (int i = 0; i < edges; ++i) {
int x = 0, y = 0, weight = 0;
std::cin >> x >> y >> weight;
adj[x].push_back(std::make_pair(weight, y));
adj[y].push_back(std::make_pair(weight, x));
graph[x].push_back(std::make_pair(weight, y));
graph[y].push_back(std::make_pair(weight, x));
}
// Selecting 1 as the starting node
minimumCost = prim(1);
std::cout << minimumCost << std::endl;
int minimum_cost = prim(1, graph);
std::cout << minimum_cost << std::endl;
return 0;
}