acwing 第60场周赛

2

去掉重复元素，不然前后相减为0

#include<iostream>
#include<algorithm>
using namespace std ;
const int N = 1e5 + 10;
int a[N];
int n , k ;
int main()
{
    cin >> n >> k ;
    for(int i = 1 ; i <= n ; i++)
    {
        cin >> a[i] ;
    }
    sort(a+1,a+1+n);
    n = unique(a + 1,a + 1 + n) - a - 1;
    int x = 1;
    for(int i = 1 ; i <=k ; i++)
    {
       
        if(i > n) cout << 0 <<endl;
        else
        {
            cout << a[i] - a[i-1] << endl;
        }
    }
    return 0 ;
}

3
动态规划

#include<iostream>
using namespace std ;
typedef long long ll ;
const int N = 2010 , mod = 998244353; 
int n ,m ,k;
ll f[N][N];
int main()
{
    cin >> n >> m >> k ;
    f[1][0] = m ;
    for(int i = 2 ; i <= n ; i++)
    {
        for(int j = 0; j <= k && j < i ; j++)
        {
            f[i][j] =  f[i-1][j];
            if(j)f[i][j] = (f[i][j] + f[i-1][j-1] * (m-1)) % mod;
        }
        
    }
    cout << f[n][k];
    return 0 ;
}