An interview question--input a bunch of random numbers (0-1000), there will be duplicate numbers, and remove them. Then arrange from largest to smallest.

1. Problem description

11
10
20
40
32
67
40
20
89
300
400
15

10
15
20//只显示1次
32
40//只显示1次
67
89
300
400

Normal algorithm:

1. Traverse all the arrays and remove duplicate numbers
2. Use the XX sorting method to sort the numbers.

Eye-catching machine algorithms

1. Generate an array of 1-1000 and give all 0
2. Input, or generate random numbers, set the array value corresponding to the random number to 1
and enter the number 15, then a[15] = 1;
3. Traverse all the arrays , if a[i]>0, output i.

#include<iostream>
using namespace std;

int main()
{
    int i, k, N, L;
    int a, Hash[1001];

    while (cin >> N)
    {
        /*初始化1000个数组*/
        for (i = 0; i<1001; i++)
            Hash[i] = 0;

        /*输入排列的数组,将这个数字的地方置1*/
        for (i = 0; i<N; i++)
        {
            cin >> a;
            Hash[a]++;
        }
        /*遍历1000个数组 如果这个地方是大于1就打印*/
        for (i = 0; i<1001; i++)
            if (Hash[i]>0)
                cout << i << endl;
    }
    return(0);
}

expand

int main()
{
    int arr[100], sum = 0;
    char c;
    int x = 4;
    while (x--)
    {
        cin >> c;
        arr[c] = 1;
    }
    for (int i = 0; i < 100; i++)
        if (arr[i] == 1)
            sum++;
    cout << sum;
    system("pause");
}