Create TopologicalSort.c

Author: techbless

Algorithm/TopologicalSort.c

@@ -0,0 +1,169 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_VERTICES 50
+
+typedef struct GraphNode {
+    int vertex;
+    struct GraphNode* link;
+} GraphNode;
+
+typedef struct GraphType {
+    int n;
+    GraphNode* adj_list[MAX_VERTICES];
+} GraphType;
+
+
+void graph_init(GraphType* g) {
+    g->n = 0;
+    for (int v = 0; v < MAX_VERTICES; v++) {
+        g->adj_list[v] = NULL;
+    }
+}
+
+
+void insert_vertext(GraphType* g, int v) {
+    if ((g->n + 1) > MAX_VERTICES) {
+        fprintf(stderr, "그래프: 정점의 개수 초과");
+        return;
+    }
+
+    g->n++;
+}
+
+
+void insert_edge(GraphType* g, int u, int v) {
+    GraphNode* node;
+    if (u >= g->n || v >= g->n) {
+        fprintf(stderr, "그래프: 정점 번호 오류");
+        return;
+    }
+
+    node = (GraphNode*)malloc(sizeof(GraphNode));
+    node->vertex = v;
+    node->link = g->adj_list[u];
+    g->adj_list[u] = node;
+}
+
+
+#define MAX_STACK_SIZE 100
+typedef int element;
+typedef struct {
+    element stack[MAX_STACK_SIZE];
+    int top;
+} StackType;
+
+
+void stack_init(StackType* s) {
+    s->top = -1;
+}
+
+
+int is_empty(StackType* s) {
+    return (s->top == -1);
+}
+
+
+int is_full(StackType* s) {
+    return (s->top == (MAX_STACK_SIZE - 1));
+}
+
+
+void push(StackType* s, element item) {
+    if (is_full(s)) {
+        fprintf(stderr, "스택 포화 에러\n");
+        return;
+    }
+    else{
+        s->stack[++(s->top)] = item;
+    }
+}
+
+
+element pop(StackType* s) {
+    if (is_empty(s)) {
+        fprintf(stderr, "스택 공백 에러\n");
+        exit(1);
+    }
+    else {
+        return s->stack[(s->top)--];
+    }
+}
+
+
+int topo_sort(GraphType* g) {
+    int i;
+    StackType s;
+    GraphNode* node;
+
+    int* in_degree = (int*)malloc(g->n * sizeof(int));
+    for (i = 0; i < g->n; i++) {
+        in_degree[i] = 0;
+    }
+
+    for (i = 0; i < g->n; i++) {
+        GraphNode* node = g->adj_list[i];
+        while (node != NULL) {
+            in_degree[node->vertex]++;
+            node = node->link;
+        }
+    }
+
+    stack_init(&s);
+
+    for (i = 0; i < g->n; i++) {
+        if (in_degree[i] == 0) {
+            push(&s, i);
+        }
+    }
+
+    while (!is_empty(&s)) {
+        int w = pop(&s);
+        printf("v[%d] -> ", w);
+        node = g->adj_list[w];
+        while (node != NULL) {
+            int u = node->vertex;
+            in_degree[u]--;
+
+            if (in_degree[u] == 0) {
+                push(&s, u);
+            }
+
+            node = node->link;
+        }
+    }
+
+    free(in_degree);
+    printf("X\n");
+    
+    return (i == g->n);
+}
+
+int main(void) {
+    GraphType g;
+
+    graph_init(&g);
+    insert_vertext(&g, 0);
+    insert_vertext(&g, 1);
+    insert_vertext(&g, 2);
+    insert_vertext(&g, 3);
+    insert_vertext(&g, 4);
+    insert_vertext(&g, 5);
+
+    insert_edge(&g, 0, 2);
+    insert_edge(&g, 0, 3);
+
+    insert_edge(&g, 1, 3);
+    insert_edge(&g, 1, 4);
+
+    insert_edge(&g, 2, 3);
+    insert_edge(&g, 2, 5);
+
+    insert_edge(&g, 3, 5);
+
+    insert_edge(&g, 4, 5);
+
+    topo_sort(&g);
+
+    return 0;
+}