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Add default param constructors, create bool query for bfs and tests

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stefiosif
2022-09-09 18:12:38 +03:00
parent a4ddc3fbe7
commit 5c1b13b400
3 changed files with 161 additions and 157 deletions
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68
algorithm/breadth_first_search.h
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@@ -1,8 +1,8 @@
#ifndef BREADTH_FIRST_SEARCH_H_
#define BREADTH_FIRST_SEARCH_H_
#include "graph/digraph.h"
#include <map>
#include <set>
#include <queue>
using namespace graph;
@@ -14,49 +14,73 @@ class BreadthFirstSearch {
public:
BreadthFirstSearch() = default;
BreadthFirstSearch(Digraph<T> G) : G(G) {}
BreadthFirstSearch(std::map<T, std::set<T>> adjMatrix)
: adjMatrix(adjMatrix) {}
// Traverse whole graph using the BFS search, and save the tree graph
// which is created when visiting new vertices (Breadth First Tree)
std::map<T, std::set<T>> execute(const T& root);
// Initialize LU table that show which vertices have been traversed
std::map<T, bool> initExplore();
private:
Graph<T> G;
};
// Search if target vertex exists in graph
bool query(const T& root, const T& target);
template<typename T>
std::map<T, bool> BreadthFirstSearch<T>::initExplore() {
std::map<T, bool> graphExplore;
for (const auto& v : G.adjMatrix) {
graphExplore[v.first] = false;
}
return graphExplore;
}
void setGraph(std::map<T, std::set<T>> adjMatrix);
private:
// Represents the graph on which the algorithm will be executed
std::map<T, std::set<T>> adjMatrix;
};
template<typename T>
std::map<T, std::set<T>> BreadthFirstSearch<T>::execute(const T& root) {
std::map<T, std::set<T>> tree;
std::map<T, bool> graphExplore = initExplore();
std::map<T, bool> visited;
std::queue<T> Q;
Q.push(root);
graphExplore[root] = true;
visited[root] = true;
while (!Q.empty()) {
const auto v = Q.front();
Q.pop();
for (const auto& u : G.adjMatrix[v]) {
if (!graphExplore[u]) {
graphExplore[u] = true;
for (const auto& u : adjMatrix[v]) {
if (!visited[u]) {
visited[u] = true;
tree[v].insert(u);
Q.push(u);
}
}
}
return tree;
}
template<typename T>
bool BreadthFirstSearch<T>::query(const T& root, const T& target) {
std::map<T, bool> visited;
std::queue<T> Q;
Q.push(root);
visited[root] = true;
while (!Q.empty()) {
const auto v = Q.front();
Q.pop();
if (v == target) return true;
for (const auto& u : adjMatrix[v]) {
if (!visited[u]) {
visited[u] = true;
Q.push(u);
}
}
}
return false;
}
template<typename T>
void BreadthFirstSearch<T>::setGraph(std::map<T, std::set<T>> adjMatrix) {
this->adjMatrix = adjMatrix;
}
} // namespace algo
#endif

74
algorithm/tarjan.h
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@@ -5,6 +5,7 @@
#include <stack>
#include <vector>
#include <ranges>
using namespace graph;
@@ -13,66 +14,73 @@ namespace algo {
template<typename T>
class Tarjan {
public:
Tarjan(Digraph<T> G) : G(G) {}
Tarjan() = default;
std::vector<SCC<T>> execute();
Tarjan(std::map<T, std::set<T>> adjMatrix) : adjMatrix(adjMatrix) {}
void strongConnect(const T& v);
auto execute();
void strongConnect(const T& u);
void setGraph(std::map<T, std::set<T>> adjMatrix);
private:
// Necessary info about vertices when running Tarjan's algorithm
struct Payload {
std::int16_t index = -1;
std::int16_t lowlink = -1;
bool onStack = false;
};
Digraph<T> G;
std::map<T, std::set<T>> adjMatrix;
std::stack<T> S;
std::int16_t index = 0;
std::map<T, Payload> p;
std::vector<SCC<T>> SCCs;
struct Vertex {
int index = -1;
int lowlink = -1;
bool onStack = false;
};
std::map<T, Vertex> vmap;
};
template<typename T>
void Tarjan<T>::strongConnect(const T& v) {
p[v].index = p[v].lowlink = index++;
p[v].onStack = true;
S.push(v);
void Tarjan<T>::strongConnect(const T& u) {
vmap[u].index = vmap[u].lowlink = index++;
S.push(u);
vmap[u].onStack = true;
for (const auto& w : G.adjMatrix[v]) {
if (p[w].index == -1) {
for (const auto& w : adjMatrix[u]) {
if (vmap[w].index == -1) {
strongConnect(w);
p[v].lowlink = std::min(p[v].lowlink, p[w].lowlink);
} else if (p[w].onStack) {
p[v].lowlink = std::min(p[v].lowlink, p[w].index);
vmap[u].lowlink = std::min(vmap[u].lowlink, vmap[w].lowlink);
} else if (vmap[w].onStack) {
vmap[u].lowlink = std::min(vmap[u].lowlink, vmap[w].index);
}
}
// If v is a root node, pop the stack and generate an SCC
if (p[v].lowlink == p[v].index) {
//std::vector<T> scc;
// If u is a root node, pop the stack and generate an SCC
if (vmap[u].lowlink == vmap[u].index) {
std::map<T, std::set<T>> scc;
bool finished = false;
do {
const auto w = S.top();
S.pop();
p[w].onStack = false;
scc[w] = G.adjMatrix[w];
finished = p[w].index == p[v].index;
vmap[w].onStack = false;
scc[w] = adjMatrix[w];
finished = (w == u);
} while (!finished);
SCCs.push_back(scc);
SCCs.push_back({ scc, static_cast<T>(vmap[u].lowlink) });
}
}
template<typename T>
std::vector<SCC<T>> Tarjan<T>::execute() {
for (auto& v : G.adjMatrix) {
if (p[v.first].index == -1) {
strongConnect(v.first);
auto Tarjan<T>::execute() {
for (const auto& u : std::views::keys(adjMatrix)) {
if (vmap[u].index == -1)
strongConnect(u);
}
return SCCs;
}
return SCCs;
template<typename T>
void Tarjan<T>::setGraph(std::map<T, std::set<T>> adjMatrix) {
this->adjMatrix = adjMatrix;
}
} // namespace algo

174
test/algorithm_test.cc
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@@ -3,79 +3,21 @@
#include "algorithm/tarjan.h"
#include "algorithm/breadth_first_search.h"
#include <random>
#include <functional>
constexpr int verticesNum = 10;
#include <iostream>
using namespace graph;
TEST_SUITE("Algorithm") {
TEST_CASE("Tarjan::execute 1") {
// 1 --> 2 --> 4 --> 1
// 2 --> 3 --> 5 --> 7 --> 3
// 5 --> 9 --> 6 --> 8 --> 9
Digraph<std::uint16_t> G;
G.insert(1, 2);
G.insert(2, 3);
G.insert(2, 4);
G.insert(3, 5);
G.insert(4, 1);
G.insert(5, 7);
G.insert(5, 9);
G.insert(6, 8);
G.insert(7, 3);
G.insert(8, 9);
G.insert(9, 6);
REQUIRE_EQ(G.adjMatrix.size(), 9);
algo::Tarjan<std::uint16_t> tarjan(G);
auto r = tarjan.execute();
std::vector<std::vector<std::uint16_t>> x = {
{6, 8, 9},
{3, 5, 7},
{1, 2, 4}
};
for (auto i = 0; i < r.size(); i++) {
auto kv = std::views::keys(r[i].adjMatrix);
CHECK_EQ(std::is_permutation(kv.begin(), kv.end(), x[i].begin()), true);
}
}
TEST_CASE("Tarjan::execute 2") {
// 1 --> 2 --> 5 --> 7 --> 2
// 1 --> 4 --> 3 --> 1
// 4 --> 6 --> 3
Digraph<std::uint16_t> G;
G.insert(1, 2);
G.insert(1, 4);
G.insert(2, 5);
G.insert(3, 1);
G.insert(4, 3);
G.insert(4, 6);
G.insert(5, 7);
G.insert(6, 3);
G.insert(7, 2);
REQUIRE_EQ(G.adjMatrix.size(), 7);
algo::Tarjan<std::uint16_t> tarjan(G);
auto r = tarjan.execute();
std::vector<std::vector<std::uint16_t>> x = {
{2, 5, 7},
{1, 3, 4, 6}
};
for (auto i = 0; i < r.size(); i++) {
auto kv = std::views::keys(r[i].adjMatrix);
CHECK_EQ(std::is_permutation(kv.begin(), kv.end(), x[i].begin()), true);
}
}
TEST_CASE("Tarjan::execute 3") {
TEST_CASE("Tarjan::execute") {
// 1 --> 2 --> 3 --> 1
// 3 --> 4 --> 5 --> 3
// 2 --> 6 --> 7 --> 8 --> 6
// 7 --> 9
// 6 --> 9 --> 10 --> 11 --> 12 --> 13 --> 9
// 12 --> 10
Digraph<std::uint16_t> G;
@@ -100,53 +42,48 @@ TEST_SUITE("Algorithm") {
REQUIRE_EQ(G.adjMatrix.size(), 13);
algo::Tarjan<std::uint16_t> tarjan(G);
auto r = tarjan.execute();
auto SCCs = algo::Tarjan<std::uint16_t>(G.adjMatrix).execute();
std::vector<std::vector<std::uint16_t>> x = {
std::vector<std::vector<std::uint16_t>> expected = {
{9, 10, 11, 12, 13},
{6, 7, 8},
{1, 2, 3, 4, 5}
};
for (auto i = 0; i < r.size(); i++) {
auto kv = std::views::keys(r[i].adjMatrix);
CHECK_EQ(std::is_permutation(kv.begin(), kv.end(), x[i].begin()), true);
for (auto i = 0; i < SCCs.size(); i++) {
auto kv = std::views::keys(SCCs[i].adjMatrix);
CHECK_EQ(std::is_permutation(kv.begin(), kv.end(),
expected[i].begin()), true);
}
}
TEST_CASE("BreadthFirstSearch::execute 1") {
// 1 --> 2 --> 5 --> 7 --> 2
// 1 --> 4 --> 3 --> 1
// 4 --> 6 --> 3
TEST_CASE("Tarjan::execute ~ DAG") {
Digraph<std::uint16_t> G;
G.insert(1, 2);
G.insert(1, 4);
G.insert(2, 5);
G.insert(3, 1);
G.insert(4, 3);
G.insert(4, 6);
G.insert(5, 7);
G.insert(6, 3);
G.insert(7, 2);
auto gen = std::bind(std::uniform_real_distribution<>(0, 1), std::default_random_engine());
algo::BreadthFirstSearch<std::uint16_t> bfs(G);
auto r = bfs.execute(1);
std::map<std::uint16_t, std::set<std::uint16_t>> x = {
{1, {2, 4}},
{2, {5}},
{4, {3, 6}},
{5, {7}}
};
CHECK_EQ(r, x);
for (int i = 0; i <= verticesNum; ++i) {
for (int j = i + 1; j <= verticesNum; ++j) {
if (gen() < 0.25) G.insert(i, j);
}
}
TEST_CASE("BreadthFirstSearch::execute 2") {
auto SCCs = algo::Tarjan<std::uint16_t>(G.adjMatrix).execute();
// Testing whether an scc is a 1-vertex scc which after the normalization
// has no edges, in this case we know tgat there exist no 2-vertex sccs
for (auto& scc : SCCs) {
CHECK_EQ(std::all_of(scc.adjMatrix.begin(), scc.adjMatrix.end(),
[](const auto& p) {
return p.second.size() == 0;
}), true);
}
}
TEST_CASE("BreadthFirstSearch::execute") {
// 1 --> 2 --> 3 --> 1
// 3 --> 4 --> 5 --> 3
// 2 --> 6 --> 7 --> 8 --> 6
// 7 --> 9
// 6 --> 9 --> 10 --> 11 --> 12 --> 13 --> 9
// 12 --> 10
Digraph<std::uint16_t> G;
@@ -169,10 +106,10 @@ TEST_SUITE("Algorithm") {
G.insert(13, 9);
G.insert(12, 10);
algo::BreadthFirstSearch<std::uint16_t> bfs(G);
auto r = bfs.execute(1);
auto tree =
algo::BreadthFirstSearch<std::uint16_t>(G.adjMatrix).execute(1);
std::map<std::uint16_t, std::set<std::uint16_t>> x = {
std::map<std::uint16_t, std::set<std::uint16_t>> expected = {
{1, {2}},
{2, {3, 6}},
{3, {4}},
@@ -185,6 +122,41 @@ TEST_SUITE("Algorithm") {
{12, {13}}
};
CHECK_EQ(r, x);
CHECK_EQ(tree, expected);
}
TEST_CASE("BreadthFirstSearch::query") {
// 1 --> 2 --> 3 --> 1
// 3 --> 4 --> 5 --> 3
// 2 --> 6 --> 7 --> 8 --> 6
// 7 --> 9
// 6 --> 9 --> 10 --> 11 --> 12 --> 13 --> 9
// 12 --> 10
Digraph<std::uint16_t> G;
G.insert(1, 2);
G.insert(2, 3);
G.insert(3, 1);
G.insert(3, 4);
G.insert(4, 5);
G.insert(5, 3);
G.insert(2, 6);
G.insert(6, 7);
G.insert(7, 8);
G.insert(7, 9);
G.insert(8, 6);
G.insert(6, 9);
G.insert(9, 10);
G.insert(10, 11);
G.insert(11, 12);
G.insert(12, 13);
G.insert(13, 9);
G.insert(12, 10);
algo::BreadthFirstSearch<std::uint16_t> bfs(G.adjMatrix);
CHECK_EQ(bfs.query(1, 5), true);
CHECK_EQ(bfs.query(1, 10), true);
CHECK_EQ(bfs.query(9, 5), false);
CHECK_EQ(bfs.query(8, 4), false);
}
}