84 lines
1.8 KiB
C++
84 lines
1.8 KiB
C++
#ifndef BREADTH_FIRST_SEARCH_H_
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#define BREADTH_FIRST_SEARCH_H_
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#include "graph/graph.h"
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#include <map>
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#include <queue>
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#include <set>
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using namespace graph;
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namespace algo {
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template <typename T> class BreadthFirstSearch {
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public:
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BreadthFirstSearch() = default;
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explicit BreadthFirstSearch(
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std::unordered_map<T, std::unordered_set<T>> adjList)
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: adjList(adjList) {}
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// Traverse whole graph using the BFS search, and save the tree graph
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// which is created when visiting new vertices (Breadth First Tree)
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std::unordered_map<T, std::unordered_set<T>> execute(const T &root);
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// Search if target vertex exists in graph
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bool query(const T &root, const T &target);
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private:
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// Represents the graph on which the algorithm will be executed
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std::unordered_map<T, std::unordered_set<T>> adjList;
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};
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template <typename T>
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std::unordered_map<T, std::unordered_set<T>>
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BreadthFirstSearch<T>::execute(const T &root) {
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std::unordered_map<T, std::unordered_set<T>> tree;
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std::unordered_map<T, bool> visited;
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std::queue<T> Q;
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Q.push(root);
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visited[root] = true;
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while (!Q.empty()) {
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const auto v = Q.front();
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Q.pop();
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for (const auto &u : adjList[v]) {
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if (!visited[u]) {
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visited[u] = true;
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tree[v].insert(u);
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tree[u];
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Q.push(u);
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}
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}
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}
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return tree;
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}
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template <typename T>
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bool BreadthFirstSearch<T>::query(const T &root, const T &target) {
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std::unordered_map<T, bool> visited;
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std::queue<T> Q;
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Q.push(root);
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visited[root] = true;
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while (!Q.empty()) {
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const auto v = Q.front();
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Q.pop();
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if (v == target)
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return true;
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for (const auto &u : adjList[v]) {
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if (!visited[u]) {
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visited[u] = true;
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Q.push(u);
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}
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}
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}
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return false;
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}
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} // namespace algo
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#endif |