s栈堆为什么损坏（Saddle）函数里，怎么取消NULL指针“p“的引用，这个警告太闹心了。

Question

#include"stdio.h"
#include"stdlib.h"
#define MAX 100
typedef struct OLNode
{
    int row, col;                            
    int v;                                    
    struct OLNode* right, * down;            
}OLNode, * OLink;
typedef struct
{
    OLNode* rhead[MAX], * chead[MAX];        
    int m, n, t;                            
}CrossList;
void CreateCrossList(CrossList* M)
{
    int m, n, i, r, c;
    OLNode* p, * q;
    printf("请输入矩阵行数和列数：");
    scanf_s("%d%d", &m, &n);
    M->m = m;
    M->n = n;
    M->t = m * n;
    for (i = 1; i <= m; i++)
        M->rhead[i] = NULL;
    for (i = 1; i <= n; i++)
        M->chead[i] = NULL;
    for (r = 1; r <= m; r++)
        for (c = 1; c <= n; c++)
        {
            p = (OLNode*)malloc(sizeof(OLNode));
            p->row = r;                                    
            p->col = c;
            printf("输入第%d行，第%d列的值：", r, c);
            scanf_s("%d", &p->v);
            p->right = NULL;
            p->down = NULL;
            if (M->rhead[r] == NULL)                    
            {
                M->rhead[r] = p;
            }
            else
            {
                if (p->col < M->rhead[r]->col)
                {
                    p->right = M->rhead[r];
                    M->rhead[r] = p;
                }
                else
                {
                    for (q = M->rhead[r]; q->right != NULL && q->right->col < c; q = q->right);
                    p->right = q->right;
                    q->right = p;
                }
            }
            if (M->chead[c] == NULL)
            {
                M->chead[c] = p;
            }
            else
            {
                if (p->row < M->chead[c]->row)
                {
                    p->down = M->chead[c];
                    M->chead[c] = p;
                }
                else
                {
                    for (q = M->chead[c]; q->down != NULL && q->down->row < r; q = q->down);
                    p->down = q->down;
                    q->down = p;
                }

            }
        }
}
void ShowMatrix(CrossList* M)
{
    int i, j;
    OLNode* p;
    int t = 1;
    for (i = 1; i <= M->m; i++)                
    {
        p = M->rhead[i];
        if (M->rhead[i])                        
            for (j = 1; j <= M->n; j++)            
                if (p->col == j)
                {
                    printf("%-4d", p->v);
                    if (p->right)
                        p = p->right;
                }
                else
                    printf("0   ");                
        else                                    
        {
            for (j = 1; j <= M->n; j++)
                printf("0   ");
        }
        printf("\n");
    }
}
void Saddle(CrossList* M)
{
    int i, j = 0, t;
    OLNode* q, * p, * max, ** Min, * s;
    Min = &s;
    s = (OLNode*)malloc(M->n + 1 * sizeof(OLNode));
    
    for (i = 1; i <= M->m; i++)
    {
        for (t = 0; t < M->n; t++)
            Min[t] = NULL;
        t = 0;
        Min[t] = M->rhead[i];
        for (p = M->rhead[i]; p; p = p->right) 
        {
            if (p->v < Min[t]->v)
            {
                Min[t] = p; 
            }
        }
        for (p = M->rhead[i]; p; p = p->right)
        {
            if (p->v == Min[t]->v && p != Min[t])
            {
                Min[++t] = p;
            }
        }
        for (t=0;Min[t];t++)
        {
            max = M->chead[Min[t]->col];
            for (q = M->chead[Min[t]->col]; q; q = q->down)
            {
                if (q->v > max->v) {
                    max = q;
                }
            }
            if (max == Min[t])
            {
                j++;
                printf("第%d个鞍点为:%-3d %-3d %-3d\n", j, max->row, max->col, max->v);
            }
        }
    }
    if (j == 0)printf("该矩阵不存在鞍点！\n");
}
void main()
{
    CrossList A;
    CreateCrossList(&A);
    printf("第一个矩阵为：\n");
    ShowMatrix(&A);
    Saddle(&A);
}