Algorithms: Graph Algorithms Tutorials and Code Examples - Page 6

Directed Cycle Detection by DFS in C++

DFS detects a directed cycle when an edge points to a vertex still active in the current search path..

cpp

int directed_cycle(const std::vector<int>& graph, int n) {
    alg_require(graph.size() <= 1000000);
    alg_require(((n >= 0) && (n <= 1000000)));
    alg_require(((int)graph.size() == alg_mul(n, n)));
    std::vector<int> color(alg_size(alg_add(n, 1)), 0);
    std::vector<int> stack(alg_size(alg_add(n, 1)), 0);
    std::vector<int> next_vertex(alg_size(alg_add(n, 1)), 0);
    int source = 0;
    int top = 0;
    int u = 0;
    int v = 0;
    while ((source < n)) {

Nov 15, 2026 C++

Algorithms: Graph Algorithms

Directed Cycle Detection by DFS in C#

DFS detects a directed cycle when an edge points to a vertex still active in the current search path..

csharp

    static int directed_cycle(ReadOnlySpan<int> graph, int n) {
        checked {
            alg_require(((n >= 0) && (n <= 1000000)));
            alg_require((graph.Length == (n * n)));
            int[] color = new int[alg_size((n + 1))];
            int[] stack = new int[alg_size((n + 1))];
            int[] next_vertex = new int[alg_size((n + 1))];
            int source = 0;
            int top = 0;
            int u = 0;
            int v = 0;
            while ((source < n)) {

Nov 15, 2026 csharp

Algorithms: Graph Algorithms

Directed Cycle Detection by DFS in PHP

DFS detects a directed cycle when an edge points to a vertex still active in the current search path..

php

function directed_cycle(array $graph, int $n): int {
    alg_require(array_is_list($graph));
    alg_require((($n >= 0) && ($n <= 1000000)));
    alg_require((count($graph) == alg_mul($n, $n)));
    $color = array_fill(0, alg_size(alg_add($n, 1)), 0);
    $stack = array_fill(0, alg_size(alg_add($n, 1)), 0);
    $next_vertex = array_fill(0, alg_size(alg_add($n, 1)), 0);
    $source = 0;
    $top = 0;
    $u = 0;
    $v = 0;
    while (($source < $n)) {

Nov 15, 2026 PHP

Algorithms: Graph Algorithms

Bipartite Graph Coloring in Java

A graph is bipartite when its vertices can be colored with two colors so that each edge joins opposite colors..

java

    static int is_bipartite(int[] graph, int n) {
        java.util.Objects.requireNonNull(graph, "graph");
        alg_require(((n >= 0) && (n <= 1000000)));
        alg_require((graph.length == Math.multiplyExact(n, n)));
        int[] color = new int[alg_size(Math.addExact(n, 1))];
        int[] queue = new int[alg_size(Math.addExact(n, 1))];
        int source = 0;
        int head = 0;
        int tail = 0;
        int u = 0;
        int v = 0;
        while ((source < n)) {

Nov 15, 2026 Java

Algorithms: Graph Algorithms

Bipartite Graph Coloring in JavaScript

A graph is bipartite when its vertices can be colored with two colors so that each edge joins opposite colors..

javascript

function is_bipartite(graph, n) {
    alg_require(graph instanceof Int32Array);
    alg_require(Number.isInteger(n) && n >= -2147483648 && n <= 2147483647);
    alg_require(((n >= 0) && (n <= 1000000)));
    alg_require((graph.length == alg_mul(n, n)));
    let color = new Int32Array(alg_size(alg_add(n, 1)));
    let queue = new Int32Array(alg_size(alg_add(n, 1)));
    let source = 0;
    let head = 0;
    let tail = 0;
    let u = 0;
    let v = 0;

Nov 15, 2026 javascript