992A - Nastya and an Array

Nastya owns too many arrays now, so she wants to delete the least important of them. However, she discovered that this array is magic! Nastya now knows that the array has the following properties:

In one second we can add an arbitrary (possibly negative) integer to all elements of the array that are not equal to zero.
When all elements of the array become equal to zero, the array explodes.

Nastya is always busy, so she wants to explode the array as fast as possible. Compute the minimum time in which the array can be exploded.

Input

The first line contains a single integer $n$ ( $1 \leq n \leq 10^{5}$ ) — the size of the array.

The second line contains $n$ integers $a_{1}, a_{2}, \dots, a_{n}$ ( $- 10^{5} \leq a_{i} \leq 10^{5}$ ) — the elements of the array.

Output

Print a single integer — the minimum number of seconds needed to make all elements of the array equal to zero.

Note

In the first example you can add $- 1$ to all non-zero elements in one second and make them equal to zero.

In the second example you can add $- 2$ on the first second, then the array becomes equal to $[0, 0, - 3]$ . On the second second you can add $3$ to the third (the only non-zero) element.

题意：一个数组里面有n个元素，现在有两种情况：

在一秒内，向所有非零元素加上一个数，可以是负数。

如果所有元素都为0，那这个数组就会爆炸。

问最少多少秒这个数组能爆炸（所有数都为0）

题解：找规律这道题是道规律题，不要去模拟，那会很复杂。对所有元素去重，非0个数就是答案。

#include<bits/stdc++.h>
using namespace std;
int n,x;
set<int>s;
int main()
{
    cin>>n;
    for(int i=0; i<n; i++)
        cin>>x,s.insert(x);
    printf("%d\n",s.size()-s.count(0));
    return 0;
}

R=lambda:map(int,input().split())
n=R()
a=R()
a=set(a)
print (len(a)) if 0 not in a else print (len(a)-1)

n=input()
a=map(int,input().split())
print(len(set(a)-{0}))

992A - Nastya and an Array

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