当我将图中的节点数从4增加到大于5时，malloc受到内存破坏

在代码中，您在Graph中分配了一个由4个Node指针组成的数组，称为head。

// Data structure to store graph
struct Graph {
    // An array of pointers to Node to represent adjacency list
    struct Node* head[N];
};

稍后，您将通过初始化内存来触摸不是您的内存：

   // initialize head pointer for all vertices
for (i = 0; i head[i] = NULL;

使用valgrind：

=16498== Invalid write of size 8
==16498==    at 0x400653: createGraph (a.c:37)
==16498==    by 0x400815: main (a.c:103)
==16498==  Address 0x52044a0 is 0 bytes after a block of size 32 alloc'd
==16498==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16498==    by 0x40063E: createGraph (a.c:33)
==16498==    by 0x400815: main (a.c:103)