C实现之单链表是否相交

  1 # include<stdio.h>
  2 struct Slist{
  3     int size;
  4     struct sl* head;
  5 };
  6 struct sl{
  7     int k;
  8     struct sl* next;
  9 };
 10 typedef struct Slist Sl;
 11 typedef struct sl sl;
 12 void init(Sl* m,int k){
 13     sl* p = (sl *)malloc(sizeof(sl));
 14     p->k = k;
 15     p->next = NULL;
 16     m->head =p;
 17     m->size = 1;
 18 }
 19
 20 sl* add(Sl* m,int key ){
 21     sl* p=(sl *)malloc(sizeof(sl));
 22     sl* q = (sl *)malloc(sizeof(sl));
 23     p->k = key;
 24     p->next = NULL;
 25     q = m->head;
 26     while (q->next != NULL)
 27         q = q->next;
 28     q->next = p;
 29     m->size++;
 30     return p;
 31 }
 32
 33 void FanZhuan(Sl* m){                            //链表反转
 34
 35     sl* p = m->head;
 36     sl* q =NULL;
 37     sl* r =NULL;
 38     while (p->next!=NULL){
 39
 40         q = p->next;
 41         p->next = r;
 42         r = p;
 43         p = q;
 44     }
 45     q->next = r;
 46     m->head = q;
 47 }
 48
 49 void BianLi(Sl* m){                                 //遍历链表
 50
 51     sl* a = m->head;
 52     printf(" \n");
 53     while (a != NULL){
 54         printf("%d",a->k);
 55         a = a->next;
 56     }
 57 }
 58
 59 sl* CheckLoop(Sl* m){                                //测试是否有环
 60     sl* a = m->head;
 61     sl* b = m->head;
 62     while (b!=NULL){
 63         a = a->next;
 64         if (b->next == NULL)
 65             return NULL;
 66         if (b->next->next == NULL)
 67             return NULL;
 68         b = b->next->next;
 69         if (a == b)
 70             return a;
 71     }
 72     return NULL;
 73 }
 74
 75 int NloopCheck(Sl* f,Sl* n){            //两者均无环，测相交
 76     sl* k1 = f->head;
 77     sl* k2 = n->head;
 78     while (k1->next!=NULL)
 79     {
 80         k1 = k1->next;
 81     }                                   //取得表k1的最后一个节点
 82     while (k2 != NULL){
 83         k2 = k2->next;
 84         if (k2 == k1)
 85         {
 86              return 1;
 87         }
 88     }
 89     return 0;
 90 }
 91
 92 void Check(Sl*t1,Sl*t2){                     //测试是否相交
 93
 94     sl* Y1 = CheckLoop(t1);                  //先测两个表的每个表是否有环
 95     sl* Y2 = CheckLoop(t2);
 96 //    if (Y1 != NULL)
 97 //        printf("The first have loop!\n");
 98 //    if (Y2 != NULL)
 99 //        printf("The second have loop!");
100
101     int y1 = (Y1 != NULL);
102     int y2 = (Y2 != NULL);
103     int y = y1 + y2;
104     int yes = 0;
105     sl* test = NULL;
106     switch (y)
107     {
108     case 0:                                       //均无环
109         printf("\n Two have no loop!");
110         yes = NloopCheck(t1, t2);
111         break;
112
113     case 1:                                       //一个有环，一个没有
114         printf("\n One Have loop!");
115         yes = 0;
116         break;
117
118     case 2:                                       //两者都有环
119         printf("\n Two have loop!");
120         test = t2->head;
121         while (1)
122         {
123             if (test == Y2)
124             {
125                 yes = 1;
126                 break;
127             }
128             test = test->next;
129         }
130         break;
131     default:
132         break;
133     }
134
135     if (yes == 1)
136         printf("\n Have intersection!");
137     else
138         printf("\n Don‘t have intersection!");
139 }
140
141 void main(){
142     Sl* t1 = (Sl*)malloc(sizeof(Sl));                 //创建带环链表t1
143     t1->size=0;
144     t1->head = NULL;
145     init(t1,8);
146     add(t1, 3);
147     add(t1, 2);
148     sl* t1Start=add(t1, 1);                           //loop start!
149     add(t1, 0);
150     add(t1, 9);
151     sl* t2Start=add(t1, 10);
152     t2Start->next = t1Start;                           //Add loop!
153
154     Sl* t2 = (Sl*)malloc(sizeof(Sl));                 //创建链表t2与t1相交
155     t2->size = 0;
156     t2->head = NULL;
157     init(t2, 8);
158     add(t2, 3);
159     add(t2, 2);
160     sl* w2 = add(t2, 1);
161     w2->next = t2Start;
162
163
164     Sl* t3 = (Sl*)malloc(sizeof(Sl));                 //创建五环链表t3
165     t3->size = 0;
166     t3->head = NULL;
167     init(t3, 8);
168     add(t3, 3);
169     add(t3, 2);
170     sl* w3= add(t3, 1);
171     add(t3,7);
172     add(t3,27);
173
174     Sl* t4 = (Sl*)malloc(sizeof(Sl));                 //创建链表t4与t3相交
175     t4->size = 0;
176     t4->head = NULL;
177     init(t4, 8);
178     add(t4, 3);
179     add(t4, 2);
180     sl* w4 = add(t4, 1);
181     w4->next = w3;
182
183     Sl* t5 = (Sl*)malloc(sizeof(Sl));                  //创建链表t5，不与上相交
184     t5->size = 0;
185     t5->head = NULL;
186     init(t5, 8);
187     add(t5, 53);
188     add(t5, 42);
189 printf("\n SingList t1 and t2:");
190 Check(t1, t2);
191 printf("\n\n SingList t3 and t4:");
192 Check(t3, t4);
193 printf("\n\n SingList t1 and t3:");
194 Check(t3, t1);
195 printf("\n\n SingList t3and t5:");
196 Check(t5, t3);
197
198
199
200
201     system("pause");
202 }

执行效果图如下：