NOI 97 (Vijos 1464)积木游戏(DP)

很普通的DP，设dp[i][j][k]为第i块积木放在第j堆且摆放状态为k的最高高度。方程很容易推出。

# include <cstdio>
# include <cstring>
# include <cstdlib>
# include <iostream>
# include <vector>
# include <queue>
# include <stack>
# include <map>
# include <set>
# include <cmath>
# include <algorithm>
using namespace std;
# define lowbit(x) ((x)&(-x))
# define pi acos(-1.0)
# define eps 1e-
# define MOD
# define INF
# define mem(a,b) memset(a,b,sizeof(a))
# define FOR(i,a,n) for(int i=a; i<=n; ++i)
# define FO(i,a,n) for(int i=a; i<n; ++i)
# define bug puts("H");
# define lch p<<,l,mid
# define rch p<<|,mid+,r
# define mp make_pair
# define pb push_back
typedef pair<int,int> PII;
typedef vector<int> VI;
# pragma comment(linker, "/STACK:1024000000,1024000000")
typedef long long LL;
int Scan() {
    int res=, flag=;
    char ch;
    if((ch=getchar())=='-') flag=;
    else if(ch>=''&&ch<='') res=ch-'';
    while((ch=getchar())>=''&&ch<='')  res=res*+(ch-'');
    return flag?-res:res;
}
void Out(int a) {
    if(a<) {putchar('-'); a=-a;}
    if(a>=) Out(a/);
    putchar(a%+'');
}
const int N=;
//Code begin...

int a[N][], dp[N][N][];

bool check(int i, int b, int j, int c)
{
    int a1, a2, b1, b2;
    if (b==) a1=, a2=;
    else if (b==) a1=, a2=;
    else a1=, a2=;
    if (c==) b1=, b2=;
    else if (c==) b1=, b2=;
    else b1=, b2=;
    return (a[i][a1]<=a[j][b1]&&a[i][a2]<=a[j][b2])||(a[i][a2]<=a[j][b1]&&a[i][a1]<=a[j][b2]);
}
int main ()
{
    int n, m;
    scanf("%d%d",&n,&m);
    FOR(i,,n) scanf("%d%d%d",&a[i][],&a[i][],&a[i][]);
    FOR(i,,n) FOR(j,,i) {
        int ma=;
        FO(k,,i) FO(l,,) ma=max(ma,dp[k][j-][l]);
        FO(l,,) dp[i][j][l]=ma+a[i][l];
        FO(k,j,i) FO(l1,,) FO(l2,,) if (check(i,l1,k,l2)) dp[i][j][l1]=max(dp[i][j][l1],dp[k][j][l2]+a[i][l1]);
    }
    int ans=;
    FOR(i,m,n) FO(j,,) ans=max(ans,dp[i][m][j]);
    printf("%d\n",ans);
    return ;
}