题目分析：

蛮简单的一道题，对于每个数拆质因子，对于每个质因子找出最长链，在每个地方枚举一下拼接

代码：

1 #include
     
       2 using namespace std; 3  4 const int maxn = 205000; 5  6 int n,a[maxn],prime[maxn],flag[maxn],minn[maxn],num,ans; 7 vector 
      
        g[maxn]; 8 vector 
       
        
          > mp[maxn]; 9 10 vector
         
           cl[maxn];11 12 void getprime(int N){13     for(int i=2;i<=N;i++){14     if(!flag[i]){prime[++num] = i,minn[i] = i;}15     for(int j=1;j<=num&&i*prime[j]<=N;j++){16         flag[i*prime[j]] = 1;17         minn[i*prime[j]] = prime[j];18         if(i%prime[j] == 0) break;19     }20     }21 }22 23 void read(){24     scanf("%d",&n);25     for(int i=1;i<=n;i++) scanf("%d",&a[i]);26     for(int i=1;i
          
           = maxx) sec = maxx,maxx = cl[z][i];53 else if(cl[z][i] > sec) sec = cl[z][i];54 }55 mp[now].push_back(make_pair(z,maxx+1));56 ans = max(ans,maxx+sec+1);57 }58 }59 60 void work(){61 getprime(200000);62 dp(1,0);63 printf("%d\n",ans);64 }65 66 int main(){67 read();68 work();69 return 0;70 }