题解 | #牛牛的单链表求和#

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

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

struct ListNode* createLinkedList(int arr[], int n) {
    if (n == 0) {
        return NULL;
    }

    struct ListNode* head = (struct ListNode*)malloc(sizeof(struct ListNode));
    head->val = arr[0];
    head->next = NULL;

    struct ListNode* curr = head;

    for (int i = 1; i < n; i++) {
        curr->next = (struct ListNode*)malloc(sizeof(struct ListNode));
        curr->next->val = arr[i];
        curr->next->next = NULL;
        curr = curr->next;
    }

    return head;
}

int sumLinkedList(struct ListNode* head) {
    int sum = 0;
    struct ListNode* curr = head;

    while (curr != NULL) {
        sum += curr->val;
        curr = curr->next;
    }

    return sum;
}

int main() {
    int n;
    scanf("%d", &n);

    int* arr = (int*)malloc(sizeof(int) * n);
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    struct ListNode* head = createLinkedList(arr, n);
    int sum = sumLinkedList(head);
    printf("%d\n", sum);

    free(arr);
    struct ListNode* curr = head;
    struct ListNode* next = NULL;

    while (curr != NULL) {
        next = curr->next;
        free(curr);
        curr = next;
    }

    return 0;
}