第15周项目2-用哈希法组织关键字
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问题:
- #include <stdio.h>
- #include <string.h>
- #define N 15
- #define M 26
- int H(char *s)
- {
- return ((*s-'a'+1)%M);
- }
-
- int main()
- {
- char *s[N]= {"if", "while", "for", "case", "do", "break", "else", "struct", "union", "int", "double", "float", "char", "long", "bool"};
- int i, j, k;
- char HT[M][10];
- int Det[M];
- for(i=0; i<M; i++)
- {
- HT[i][0]='\0';
- Det[i]=0;
- }
- printf("字符串 key\tH(key)\n");
- printf("------------------------\n");
- for(i=0; i<N; i++)
- {
- j=H(s[i]);
- printf("%s\t\t%d\n", s[i],j);
- k=0;
- while(1)
- {
- k++;
- if(HT[j][0]=='\0')
- {
- strcpy(HT[j], s[i]);
- break;
- }
- else
- {
- j=(j+1)%M;
- }
- }
- Det[j]=k;
- }
- printf("---------------------\n");
- printf("哈希表\n");
- printf("位置\t字符串\t探查次数\n");
- printf("---------------------\n");
- for(i=0; i<M; i++)
- printf("%d\t%s\t%d\n", i, HT[i], Det[i]);
- printf("---------------------\n");
- k=0;
- for(i=0; i<M; i++)
- k+=Det[i];
- printf("查找成功情况下的平均查找长度 %f\n", 1.0*k/N);
- return 0;
- }
运行结果:
- #include <stdio.h>
- #include <string.h>
- #include <malloc.h>
- #define N 15
- #define M 26
- typedef struct node
- {
- char *key;
- struct node *next;
- } LNode;
-
- typedef struct
- {
- LNode *link;
- } HTType;
-
- int H(char *s)
- {
- return ((*s-'a'+1)%M);
- }
-
-
- void Hash(char *s[], HTType HT[])
- {
- int i, j;
- LNode *q;
- for(i=0; i<M; i++)
- HT[i].link=NULL;
- for(i=0; i<N; i++)
- {
- q=(LNode*)malloc(sizeof(LNode));
- q->key = (char*)malloc(sizeof(strlen(s[i])+1));
- strcpy(q->key, s[i]);
- q->next=NULL;
- j=H(s[i]);
- if(HT[j].link==NULL)
- HT[j].link=q;
- else
- {
- q->next = HT[j].link;
- HT[j].link=q;
- }
- }
- }
-
-
- void DispHT(HTType HT[])
- {
- int i;
- LNode *p;
- printf("哈希表\n");
- printf("位置\t关键字序列\n");
- printf("---------------------\n");
- for(i=0; i<M; i++)
- {
- printf(" %d\t", i);
- p=HT[i].link;
- while(p!=NULL)
- {
- printf("%s ", p->key);
- p=p->next;
- }
- printf("\n");
- }
- printf("---------------------\n");
- }
-
-
- double SearchLength1(char *s[], HTType HT[])
- {
- int i, k, count = 0;
- LNode *p;
- for(i=0; i<N; i++)
- {
- k=0;
- p=HT[H(s[i])].link;
- while(p!=NULL)
- {
- k++;
- if(strcmp(p->key, s[i])==0)
- break;
- p=p->next;
- }
- count+=k;
- }
- return 1.0*count/N;
- }
-
-
- double SearchLength2(HTType HT[])
- {
- int i, k, count = 0;
- LNode *p;
- for(i=0; i<M; i++)
- {
- k=0;
- p=HT[i].link;
- while(p!=NULL)
- {
- k++;
- p=p->next;
- }
- count+=k;
- }
- return 1.0*count/M;
- }
- int main()
- {
- HTType HT[M];
- char *s[N]= {"if", "while", "for", "case", "do", "break", "else", "struct", "union", "int", "double", "float", "char", "long", "bool"};
- Hash(s, HT);
- DispHT(HT);
- printf("查找成功情况下的平均查找长度 %f\n", SearchLength1(s, HT));
- printf("查找不成功情况下的平均查找长度 %f\n", SearchLength2(HT));
- return 0;
- }
运行结果:
0 0