蓝桥杯 历届试题 对局匹配(DP)

题目链接:http://lx.lanqiao.cn/problemset.page?code=PREV-&userid=162162

#include<bits/stdc++.h>
using namespace std;

#define debug puts("YES");
#define rep(x,y,z) for(int (x)=(y);(x)<(z);(x)++)
#define ll long long

#define lrt int l,int r,int rt
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define root l,r,rt
#define mst(a,b) memset((a),(b),sizeof(a))
#define pii pair<int,int>
#define fi first
#define se second
#define mk(x,y) make_pair(x,y)
const int mod=1e9+7;
const int maxn=1e5+5;
const int ub=1e6;
ll powmod(ll x,ll y){ll t; for(t=1;y;y>>=1,x=x*x%mod) if(y&1) t=t*x%mod; return t;}
ll gcd(ll x,ll y){return y?gcd(y,x%y):x;}
int n,k;
int v[maxn];
int dp[maxn][2];
int main(){
    cin>>n>>k;
    rep(i,0,n){
        int x;cin>>x;
        v[x]++;
    }
    if(k==0){
        int ans=0;
        rep(i,0,maxn) if(v[i]) ans++;
        cout<<ans<<endl;
    }else{
        rep(i,0,maxn){
            if(i<k) {dp[i][1]=v[i];continue;}
            dp[i][0]=max(dp[i-k][0],dp[i-k][1]);
            dp[i][1]=dp[i-k][0]+v[i];
            mst(dp[i-k],0);
        }
        int ans=0;
        rep(i,0,maxn) ans+=max(dp[i][0],dp[i][1]);
        cout<<ans<<endl;
    }
    return 0;
}