c_cpp 给定一个链接的线段列表，删除中间点

Posted 2021-05-14

//https://www.geeksforgeeks.org/given-linked-list-line-segments-remove-middle-points/
#include <iostream>
#include <list>
using namespace std;

struct linked_list {
    int x,y;
    struct linked_list *next;
};
typedef struct linked_list node;

void print (node *n) {
    while (n) {
        cout<< "("<<n->x << "," << n->y << ")"<< "->";
        n=n->next;
    }
    cout<< "NULL";
}

void insert (node **headref, int n, int m) {
    node *temp= (node*)malloc(sizeof(node));
    temp->x=n;
    temp->y=m;
    temp->next=NULL;
    if (*headref==NULL) {
        *headref=temp;
        return;
    }
    node *last=*headref;
    while (last->next)
        last=last->next;
    last->next=temp;
    return;
}

void RemoveMiddle (node **headref) {
    if (*headref==NULL || (*headref)->next==NULL || (*headref)->next->next==NULL)
        return;
    node *next=(*headref)->next, *next2= next->next;
    if ((*headref)->x==next->x) {
        while (next2!=NULL && next->x == next2->x) {
            free(next);
            next=next2;
            next2=next2->next;
        }
        (*headref)->next=next;
    }
    else if ((*headref)->y==next->y) {
        while (next2!=NULL && next->y == next2->y) {
            free(next);
            next=next2;
            next2=next2->next;
        }
        (*headref)->next=next;
    }
    else
        return;
    RemoveMiddle(&((*headref)->next));
    return;
}

int main() {
    int n,m;
    node *head=NULL;
    while (true) {
        cout<< "Enter x & y: ";
        cin>>n>>m;
        if (n==-9 && m==-9)
            break;
        else
            insert (&head,n,m);
    }
    print(head);
    RemoveMiddle(&head);
    cout<< "\n";
    print(head);
}