牛客小白月赛30J

J dp B站讲解视频 https://www.bilibili.com/video/BV1GT4y1M78d?p=5

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
//typedef __int128 INT;
typedef double db;
typedef vector<int> vii;
typedef vector<ll> vll;
typedef pair<int,int> PII;
#define so sizeof
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define fi first
#define se second
#define mp make_pair
#define ub upper_bound
const db esp=1e-5;
const int N=2e5+10,M=2e5+10,Max=2e5,inf=0x3f3f3f3f,mod=998244353;
const ll INF=0x3f3f3f3f3f3f3f3f;

int n,a;
ll num[N],dp[N][2];

void work(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        scanf("%d",&a);
        num[a]++;
    }
    for(int i=1;i<=Max;i++){
        dp[i][0]=max(dp[i-1][1],dp[i-1][0]);
        dp[i][1]=dp[i-1][0]+num[i]*i;
    }
    cout<<max(dp[Max][0],dp[Max][1])<<endl;
    return ;
}


int main(){
        work();
    return 0;
}