单链表中的元素以值非递减有序排列，用C语言写一算法，删除表中所有值相同的多余元素，同时释放被删结点空间。

以下是删除单链表中所有值相同的多余元素的C语言算法：

#include <stdio.h>
#include <stdlib.h>

typedef struct ListNode {
    int val;
    struct ListNode *next;
} ListNode;

void deleteDuplicates(ListNode *head) {
    if (head == NULL) {
        return;
    }
    ListNode *prev = head;
    ListNode *cur = head->next;
    while (cur != NULL) {
        if (cur->val == prev->val) {
            prev->next = cur->next;
            free(cur);
            cur = prev->next;
        } else {
            prev = cur;
            cur = cur->next;
        }
    }
}

int main() {
    ListNode *head = (ListNode *)malloc(sizeof(ListNode));
    head->val = 1;
    head->next = (ListNode *)malloc(sizeof(ListNode));
    head->next->val = 1;
    head->next->next = (ListNode *)malloc(sizeof(ListNode));
    head->next->next->val = 2;
    head->next->next->next = (ListNode *)malloc(sizeof(ListNode));
    head->next->next->next->val = 3;
    head->next->next->next->next = NULL;

    deleteDuplicates(head);

    ListNode *cur = head;
    while (cur != NULL) {
        printf("%d ", cur->val);
        cur = cur->next;
    }
    printf("\n");

    return 0;
}

这个算法的时间复杂度是O(n)，其中n是单链表中的元素个数。