c语言-leetcode 0002-add-two-numbers.zip

#include <stdio.h> #include <stdlib.h> #include <string.h> /* Definition for singly-linked list. */ struct ListNode { int val; struct ListNode *next; }; struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) { int carry = 0; struct ListNode dummy; struct ListNode *p = l1, *prev = &dummy; dummy.next = p; while (l1 != NULL || l2 != NULL) { int sum = 0; if (l1 != NULL) { sum += l1->val; l1 = l1->next; } if (l2 != NULL) { if (p == NULL) { /* l2 longer than l1 */ prev->next = l2; p = l2; } sum += l2->val; l2 = l2->next; } sum += carry; carry = sum / 10; p->val = sum % 10; prev = p; p = p->next; } if (carry) { p = malloc(sizeof(*p)); p->val = carry; p->next = NULL; prev->next = p; } return dummy.next; } static struct ListNode *node_build(const char *digits) { struct ListNode *res, *p, *prev; int first = 1; int len = strlen(digits); const char *c = digits + len - 1; prev = NULL; while (len-- > 0) { p = malloc(sizeof(*p)); if (first) { first = 0; res = p; } p->val = *c-- - '0'; p->next = NULL; if (prev != NULL) { prev->next = p; } prev = p; } return res; } static void show(struct ListNode *ln) { int sum = 0, factor = 1; while (ln != NULL) { sum += ln->val * factor; factor *= 10; ln = ln->next; } printf("%d\n", sum); } int main(int argc, char **argv) { if (argc < 3) { fprintf(stderr, "Usage: ./test n1 n2\n"); exit(-1); } struct ListNode *l1 = node_build(argv[1]); struct ListNode *l2 = node_build(argv[2]); struct ListNode *res = addTwoNumbers(l1, l2); show(l1); show(l2); show(res); return 0; }