十字链表的创建

#include <stdio.h>
#include <stdlib.h>
typedef int ElemType;
typedef int Status;

typedef struct OLNode{
    int col, row;
    ElemType value;
    struct OLNode *down, *right;
}OLNode, *OLink;

typedef struct{
    OLink *rhead, *chead;//行、列链表头指针
    int mu, nu, tu;
}CrossList;

Status CreateSMatrix_OL(CrossList *M){//创建稀疏矩阵M， 采用十字链表存储
    int m, n, t;
    int i, j, v;
    OLink p, q;
    if(M){
        free(M);
    }
    scanf("%d%d%d", &m, &n, &t);
    M -> mu = m;
    M -> nu = n;
    M -> tu = t;
    M -> rhead = (OLink *)malloc((m + 1) * sizeof(OLink));
    M -> chead = (OLink *)malloc((n + 1) * sizeof(OLink));
    if(! M -> rhead){
        exit(0);
    }
    if(! M -> chead){
        exit(0);
    }
    M -> rhead = M -> chead = NULL;//初始化行列头指针向量，各行列链表为空
    for(scanf("%d%d%d", &i, &j, &v); i != 0;scanf("%d%d%d", &i, &j, &v)){
        p = (OLink )malloc((m + 1) * sizeof(OLink));
        if(!p){
            exit(0);
        }
        p -> col = i;
        p -> row = j;
        p -> value = v;
        if(M -> rhead[i] == NULL || M -> rhead[i] -> row > j){
            p -> right = M -> rhead[i];
            M -> rhead[i] = p;
        }
        else{//寻找在行表中的插入位置
            for(q = M -> rhead[i]; (q -> right) && q -> right -> col < j; q = q -> right);
            p -> right = q -> right;
            q -> right = p;
        }//完成行插入
        if(M -> chead[j] == NULL || M -> chead[j] -> row > i){
            p -> down = M -> chead[j];
            M -> chead[j] = p;
        }
        else{//寻找在列表中的插入位置
            for(q = M -> chead[j]; (q -> down) && q -> down -> row < i; q = q -> down);
            p -> down = q -> down;
            q -> down = p;
        }
    }
    return 1;
}