Cả hai tìm kiếm nhị phân và tìm kiếm tuần tự hoặc tuyến tính đều được sử dụng trong lập trình máy tính để tìm kiếm một phần tử. Độ phức tạp về thời gian của Tìm kiếm nhị phân là O (log (n)) và Tìm kiếm tuần tự là O (n).
Thuật toán
Begin Algorithm for Binary Search: BinarySearch() function with ‘arr’ the array of data and ‘n’ the number of values, start and end index, iteration count and element to be searched in the argument list. Increment iteration counter and compare the item value with the a[mid]. If item < a[mid] choose first half otherwise second half to proceed further. Return iteration value on successful search. End
Mã mẫu
#include<iostream> using namespace std; int BinarySearch(int a[], int start, int end, int item, int iter) { int i, mid; cout<<"\niteration "<<iter+1; iter++; mid = start + (end-start+1)/2; if(item > a[end] || item < a[start] || mid == end) { cout<<"\nNot found"; return iter; } else if(item == a[mid]) { cout<<"\n item found at "<<mid<<" index."; return iter; } else if(item == a[start]) { cout<<"\n item found at "<<start<<" index."; return iter; } else if(item == a[end]) { cout<<"\n item found at "<<end<<" index."; return iter; } else if(item > a[mid]) BinarySearch(a, mid, 9, item, iter); else BinarySearch(a, start, mid, item, iter); } int LinearSearch(int a[], int n, int item) { int i; for(i = 0; i < n; i++) { cout<<"\niteration "<<i+1; if(a[i] == item) { cout<<"\n item found at "<<i<<" index."; return i+1; } } cout<<"\nNot found"; } int main() { int n, i, B, L, a[10]={2, 7, 14, 24, 26, 35, 38, 41, 49, 53}; cout<<"\nEnter the element to be searched: "; cin>>n; cout<<"\n\n\t\t\tBinary Search :"; B = BinarySearch(a, 0, 9, n, 0); cout<<"\n\n\t\t\tLinear Search :"; L = LinearSearch(a, 10, n); if(L > B) cout<<"\n\nBinary search is better for this search."; else if(L < B) cout<<"\n\nLinear search is better for this search."; else cout<<"\n\nBoth are equally efficient for this search."; return 0; }
Đầu ra
Enter the element to be searched: 7 Binary Search : iteration 1 iteration 2 iteration 3 iteration 4 item found at 1 index. Linear Search : iteration 1 iteration 2 item found at 1 index. Linear search is better for this search. Enter the element to be searched: 53 Binary Search : iteration 1 item found at 9 index. Linear Search : iteration 1 iteration 2 iteration 3 iteration 4 iteration 5 iteration 6 iteration 7 iteration 8 iteration 9 iteration 10 item found at 9 index. Binary search is better for this search. Enter the element to be searched: 1 Binary Search : iteration 1 Not found Linear Search : iteration 1 iteration 2 iteration 3 iteration 4 iteration 5 iteration 6 iteration 7 iteration 8 iteration 9 iteration 10 Not found Binary search is better for this search.