第十四周 專案1驗證演算法
阿新 • • 發佈:2019-01-06
折半查詢
#include <stdio.h> #define MAXL 100 typedef int KeyType; typedef char InfoType[10]; typedef struct { KeyType key; //KeyType為關鍵字的資料型別 InfoType data; //其他資料 } NodeType; typedef NodeType SeqList[MAXL]; //順序表型別 int BinSearch(SeqList R,int n,KeyType k) { int low=0,high=n-1,mid; while (low<=high) { mid=(low+high)/2; if (R[mid].key==k) //查詢成功返回 return mid+1; if (R[mid].key>k) //繼續在R[low..mid-1]中查詢 high=mid-1; else low=mid+1; //繼續在R[mid+1..high]中查詢 } return 0; } int main() { int i,n=10; int result; SeqList R; KeyType a[]= {1,3,9,12,32,41,45,62,75,77},x=75; for (i=0; i<n; i++) R[i].key=a[i]; result = BinSearch(R,n,x); if(result>0) printf("序列中第 %d 個是 %d\n",result, x); else printf("木有找到!\n"); return 0; }
遞迴的折半查詢
#include <stdio.h> #define MAXL 100 typedef int KeyType; typedef char InfoType[10]; typedef struct { KeyType key; //KeyType為關鍵字的資料型別 InfoType data; //其他資料 } NodeType; typedef NodeType SeqList[MAXL]; //順序表型別 int BinSearch1(SeqList R,int low,int high,KeyType k) { int mid; if (low<=high) //查詢區間存在一個及以上元素 { mid=(low+high)/2; //求中間位置 if (R[mid].key==k) //查詢成功返回其邏輯序號mid+1 return mid+1; if (R[mid].key>k) //在R[low..mid-1]中遞迴查詢 BinSearch1(R,low,mid-1,k); else //在R[mid+1..high]中遞迴查詢 BinSearch1(R,mid+1,high,k); } else return 0; } int main() { int i,n=10; int result; SeqList R; KeyType a[]= {1,3,9,12,32,41,45,62,75,77},x=75; for (i=0; i<n; i++) R[i].key=a[i]; result = BinSearch1(R,0,n-1,x); if(result>0) printf("序列中第 %d 個是 %d\n",result, x); else printf("木有找到!\n"); return 0; }