1097 Deduplication on a Linked List (25point(s)) - C語言 PAT 甲級

1097 Deduplication on a Linked List (25point(s))

Given a singly linked list L with integer keys, you are supposed to remove the nodes with duplicated absolute values of the keys. That is, for each value K, only the first node of which the value or absolute value of its key equals K will be kept. At the mean time, all the removed nodes must be kept in a separate list. For example, given L being 21→-15→-15→-7→15, you must output 21→-15→-7, and the removed list -15→15.

Input Specification:

Each input file contains one test case. For each case, the first line contains the address of the first node, and a positive N (≤10⁵) which is the total number of nodes. The address of a node is a 5-digit nonnegative integer, and NULL is represented by −1.

Then N lines follow, each describes a node in the format:

Address Key Next

where Address is the position of the node, Key is an integer of which absolute value is no more than 10⁴, and Next is the position of the next node.

Output Specification:

For each case, output the resulting linked list first, then the removed list. Each node occupies a line, and is printed in the same format as in the input.

Sample Input:

00100 5
99999 -7 87654
23854 -15 00000
87654 15 -1
00000 -15 99999
00100 21 23854

Sample Output:

00100 21 23854
23854 -15 99999
99999 -7 -1
00000 -15 87654
87654 15 -1

題目大意：

輸入一個鏈表，去重絕對值相等的節點，先輸出去重後的節點，後輸出被刪除的節點

設計思路：

• 第一遍遍歷，利用 num[] 數組輸出絕對值不重複的節點，並把輸出的節點標記
• 第二遍遍歷，輸出未被標記的節點

編譯器：C (gcc)

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

struct node {
        int d, next;
        int flag;
};

int main(void)
{
        int root, n, root2 = -1;
        struct node list[100000] = {0};
        int num[10010] = {0};
        int i, t, f;

        scanf("%d%d", &root, &n);
        for (i = 0; i < n; i++) {
                scanf("%d", &t);
                scanf("%d%d", &list[t].d, &list[t].next);
        }
        f = 0;
        i = root;
        if (i != -1) {
                f = 1;
                printf("%05d %d ", i, list[i].d);
                list[i].flag = 1;
                num[abs(list[i].d)] = 1;
                i = list[i].next;
        }
        while (i != -1) {
                if (num[abs(list[i].d)] == 0) {
                        printf("%05d\n%05d %d ", i, i, list[i].d);
                        list[i].flag = 1;
                        num[abs(list[i].d)] = 1;
                } else {
                        if (root2 < 0)
                                root2 = i;
                }
                i = list[i].next;
        }
        if (f == 1)
                printf("-1\n");
        f = 0;
        i = root2;
        if (i != -1) {
                f = 1;
                printf("%05d %d ", i, list[i].d);
                i = list[i].next;
        }
        while (i != -1) {
                if (list[i].flag == 0)
                        printf("%05d\n%05d %d ", i, i, list[i].d);
                i = list[i].next;
        }
        if (f == 1)
                printf("-1\n");
        return 0;
}