[CTSC2001] tree

#include <bits/stdc++.h>
#define rep(_i, _j) for(int _i = 1; _i <= _j; ++_i)
const int inf = 0x3f3f3f3f;
typedef long long LL;
typedef double DB;
using namespace std;
const int maxn = 4 * 31 * 31;
const int maxv = maxn;
const int maxe = maxv * 3 * 2;

int n, base, val[maxn];

struct Edge {
    int edge;
    int head[maxn], to[maxe], next[maxe];
    Edge() {
        edge = 0;
        memset(head, -1, sizeof head);
    }
    void addedge(int u, int v) {
        to[edge] = v;
        next[edge] = head[u];
        head[u] = edge++;    
        to[edge] = u;
        next[edge] = head[v];
        head[v] = edge++;
    }
} E;
inline int id(int face, int row, int col) {
    return face * base + col + ((1 + (row - 1) * 2 + 1) * (row) / 2);
}
void link_face(int a, int b) {
    for(int i = 0; i < n; ++i) {
        E.addedge(id(a, i, 0), id(b, i, i * 2));
    }
}

int f[maxn][maxn];
int dfs(int fa, int lim) {
    int &Ranma = f[fa][lim];
    if(Ranma != 0) return Ranma;
    else Ranma = 1;
    for(int i = E.head[fa]; i != -1; i = E.next[i]) {
        if((val[fa] < val[E.to[i]] && val[E.to[i]] < lim) || (lim < val[E.to[i]] && val[E.to[i]] < val[fa])) {
            Ranma = max(Ranma, dfs(E.to[i], lim) + dfs(E.to[i], val[fa]));
        }
    }
    return Ranma;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin); freopen("data.out", "w", stdout);
#endif
    scanf("%d", &n);
    base = n * n;
    for(int i = 0; i < 4; ++i) {
        for(int j = 0; j < n; ++j) {
            for(int k = 0; k < j * 2 + 1; ++k) {
                int id_now = id(i, j, k);
                scanf("%d", &val[id_now]);
                if(k != 0) {
                    E.addedge(id_now, id(i, j, k - 1));
                }
                if((k & 1) && j != 0) {
                    E.addedge(id_now, id(i, j - 1, k - 1));
                }
            }
        }
    }
    link_face(0, 2), link_face(2, 1), link_face(1, 0);
    for(int i = 0; i < n; ++i) {
        E.addedge(id(0, n - 1, i * 2), id(3, n - i - 1, 0));
        E.addedge(id(2, n - 1, i * 2), id(3, n - 1, (n - 1) * 2 - i * 2));
        E.addedge(id(1, n - 1, i * 2), id(3, i, i * 2));
    }
    int Akane;
    for(int i = 0; i < 4 * base; ++i) {
        Akane = max(Akane, dfs(i, 0) + dfs(i, 4 * base + 1) - 1);
    }
    printf("%d\n", Akane);

    return 0;
}