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Graph Class

Lesson 3 of 14 in Coddy's Graphs - Data Structures Series #9 course.

The Graph class is built around a single field, vertices, which is the adjacency list: a map from each vertex key to the list of its neighbors. Every operation we add later (adding edges, listing neighbors, removing edges) is just a small change to this map.

The constructor starts the graph in its empty state: no vertices, no edges. So the map is just an empty map. The methods we add in the next lessons will grow it.

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Challenge

Easy

Write a class Graph with a constructor that takes no input.

Initialize a single field vertices as an empty map (or your language's equivalent of a key-to-list adjacency map).

Try it yourself

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "graph.h"

static int _cmp_int(const void* a, const void* b) {
    int ai = *(const int*)a, bi = *(const int*)b;
    return (ai > bi) - (ai < bi);
}

int main() {
    Graph g;
    Graph_init(&g);
    char line[1024];
    while (fgets(line, sizeof(line), stdin)) {
        line[strcspn(line, "\r\n")] = '\0';
        char* cmd = strtok(line, " \t");
        if (!cmd) continue;
        if (strcmp(cmd, "verticesEmpty") == 0) { printf("%s\n", g.vertexCount == 0 ? "true" : "false"); }
    }
    return 0;
}

All lessons in Graphs - Data Structures Series #9