5658845 4520125 7895122 8777541 8451277 1302850 80801524568555 5552012 5050552 7825877 1250255 1005231 65452313852085 7576651 7881200 4581002
1、算法分析
先用选择排序法装饰所给的账号排序,然后采用二分查找算法检验输入账号的合法性。
2、参考代码
#include
using namespace std;
int binarysearch(int a[],int n=10,int value=0000000);
void selectionsort(int a[],int n=10);
int main()
{
int test[]={5658845,4520125,7895122,8777541,8451277,1302850,8080152,4568555,5552012,5050552,7825877,1250255,1005231,6545231,3852085,7576651,7881200,4581002};
int accounts;selectionsort(test,18);
cout<<”请输入要查找的账号:”;
cin>>accounts;
if(binarysearch(test,sizeof(test)/sizeof(test[0]),accounts))
cout<<”合法账号!”<;
else
cout<<”非法账号!”<;
return 0;
}
//选择排序函数void selectionsort(int a[],int n)
//二分查找函数int binarysearch(int a[],int n,int value)
#include <iostream>
using namespace std;
void swap(int *a, int *b) {
int t = *a;
*a = *b;
*b = t;
}
void selectionsort(int a[], int n) {
for (int i = 0; i < n - 1; i++) {
int min_idx = i;
for (int j = i + 1; j < n; j++)
if (a[j] < a[min_idx])
min_idx = j;
if (min_idx != i)
swap(&a[min_idx], &a[i]);
}
}
int binarysearch(int a[], int n, int value) {
int left = 0, right = n - 1;
while (left <= right) {
int m = (left + right) / 2;
if (a[m] < value)
left = m + 1;
else if (a[m] > value)
right = m - 1;
else
return m;
}
return -1;
}
int main() {
int test[] = {5658845, 4520125, 7895122, 8777541, 8451277, 1302850,
8080152, 4568555, 5552012, 5050552, 7825877, 1250255,
1005231, 6545231, 3852085, 7576651, 7881200, 4581002};
std::size_t size = sizeof(test) / sizeof(int);
selectionsort(test, size);
cout << "请输入要查找的账号:";
int account;
cin >> account;
int index = binarysearch(test, size, account);
if (index >= 0 && index < size)
cout << "合法账号!" << endl;
else
cout << "非法账号!" << endl;
return 0;
}