【ZOJ】3209 Treasure Map

#include<cstdio>
#include<algorithm>
#define INF 0x7FFFFFFF
#define MAXN 450010
using namespace std;
int L[MAXN], R[MAXN], U[MAXN], D[MAXN], H[MAXN];
int n, m, p, size, ans, C[MAXN], S[MAXN];
void Init() {
    int i;
    n *= m;
    for (i = 0; i <= n; i++) {
        S[i] = 0;
        L[i + 1] = i;
        R[i] = i + 1;
        U[i] = D[i] = i;
    }
    R[n] = 0;
    size = n + 1;
}
void Remove(int c) {
    int i, j;
    L[R[c]] = L[c];
    R[L[c]] = R[c];
    for (i = D[c]; i != c; i = D[i]) {
        for (j = R[i]; j != i; j = R[j]) {
            U[D[j]] = U[j];
            D[U[j]] = D[j];
            S[C[j]]--;
        }
    }
}
void Resume(int c) {
    int i, j;
    L[R[c]] = c;
    R[L[c]] = c;
    for (i = D[c]; i != c; i = D[i]) {
        for (j = R[i]; j != i; j = R[j]) {
            U[D[j]] = j;
            D[U[j]] = j;
            S[C[j]]++;
        }
    }
}
inline void Link(int r, int c) {
    U[size] = c;
    D[size] = D[c];
    U[D[c]] = size;
    D[c] = size;
    if (H[r] < 0)
        H[r] = L[size] = R[size] = size;
    else {
        L[size] = H[r];
        R[size] = R[H[r]];
        L[R[H[r]]] = size;
        R[H[r]] = size;
    }
    S[c]++;
    C[size++] = c;
}
void Dance(int now) {
    if (R[0] == 0)
        ans = min(ans, now);
    else {
        int i, j, c, temp;
        for (temp = INF,i = R[0]; i; i = R[i]) {
            if (S[i] < temp) {
                c = i;
                temp = S[i];
            }
        }
        Remove(c);
        for (i = D[c]; i != c; i = D[i]) {
            for (j = R[i]; j != i; j = R[j])
                Remove(C[j]);
            Dance(now + 1);
            for (j = L[i]; j != i; j = L[j])
                Resume(C[j]);
        }
        Resume(c);
    }
}
int main() {
    int c, i, j, k, x1, y1, x2, y2;
    scanf("%d", &c);
    while (c--) {
        scanf("%d%d%d", &n, &m, &p);
        Init();
        for (i = 1; i <= p; i++) {
            H[i] = -1;
            scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
            for (j = x1 + 1; j <= x2; j++) {
                for (k = y1 + 1; k <= y2; k++)
                    Link(i, (j - 1) * m + k);
            }
        }
        ans = INF;
        Dance(0);
        if (ans != INF)
            printf("%d\n", ans);
        else
            puts("-1");
    }
    return 0;
}