luogu4728 双递增序列 (dp)

 1 #include<bits/stdc++.h>
 2 #define CLR(a,x) memset(a,x,sizeof(a))
 3 #define MP make_pair
 4 using namespace std;
 5 typedef long long ll;
 6 typedef unsigned long long ull;
 7 typedef pair<int,int> pa;
 8 const int maxn=2e3+10;
 9 
10 inline ll rd(){
11     ll x=0;char c=getchar();int neg=1;
12     while(c<‘0‘||c>‘9‘){if(c==‘-‘) neg=-1;c=getchar();}
13     while(c>=‘0‘&&c<=‘9‘) x=x*10+c-‘0‘,c=getchar();
14     return x*neg;
15 }
16 
17 int M,N,a[maxn],tmp[maxn],f[maxn][maxn];
18 
19 int main(){
20     //freopen("","r",stdin);
21     int i,j,k;
22     for(M=rd();M;M--){
23         N=rd();
24         for(i=1;i<=N;i++) a[i]=tmp[i]=rd();
25         sort(tmp+1,tmp+N+1);int m=unique(tmp+1,tmp+N+1)-tmp;
26         for(i=1;i<=N;i++)
27             a[i]=lower_bound(tmp+1,tmp+m,a[i])-tmp;
28         CLR(f,127);
29         f[1][1]=0;
30         for(i=1;i<N;i++){
31             for(j=0;j<m;j++){
32                 if(a[i+1]>f[i][j]) f[i+1][i+1-j]=min(f[i+1][i+1-j],a[i]);
33                 if(a[i+1]>a[i]) f[i+1][j+1]=min(f[i+1][j+1],f[i][j]);
34             }
35         }
36         if(f[N][N>>1]<=1e8) printf("Yes!\n");
37         else printf("No!\n");
38     }
39     return 0;
40 }