【HDU】3335 Divisibility

#include<cstdio>
#include<algorithm>
#define MAXM 1010
#define MAXN 1000000
#define INF 0x7FFFFFFF
typedef long long LL;
using namespace std;
LL a[MAXM];
int size, ans;
int L[MAXN], R[MAXN], U[MAXN], D[MAXN];
int H[MAXN], C[MAXN], S[MAXN];
void Init(int n) {
    int i;
    for (i = 0; i <= n; i++) {
        R[i] = i + 1;
        L[i + 1] = i;
        U[i] = D[i] = i;
        S[i] = 0;
        H[i] = -1;
    }
    R[n] = 0;
    size = n + 1;
}
void Link(int r, int c) {
    D[size] = D[c];
    U[size] = 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;
}
int A() {
    int i, res;
    for (res = 0, i = R[0]; i; i = R[i])
        res++;
    return res;
}
void Remove(int c) {
    int i;
    for (i = D[c]; i != c; i = D[i]) {
        L[R[i]] = L[i];
        R[L[i]] = R[i];
    }
}
void Resume(int c) {
    int i;
    for (i = D[c]; i != c; i = D[i])
        L[R[i]] = R[L[i]] = i;
}
void Dance(int now) {
    if (R[0] == 0)
        ans = max(ans, now);
    else if (now + A() > ans) {
        int i, j, temp, c;
        for (temp = INF,i = R[0]; i; i = R[i]) {
            if (temp > S[i]) {
                temp = S[i];
                c = i;
            }
        }
        for (i = D[c]; i != c; i = D[i]) {
            Remove(i);
            for (j = R[i]; j != i; j = R[j])
                Remove(j);
            Dance(now + 1);
            for (j = L[i]; j != i; j = L[j])
                Resume(j);
            Resume(j);
        }
    }
}
int main() {
    int c, i, j, n;
    scanf("%d", &c);
    while (c--) {
        scanf("%d", &n);
        Init(n);
        for (i = 1; i <= n; i++)
            scanf("%I64d", &a[i]);
        for (i = 1; i <= n; i++) {
            for (j = 1; j <= n; j++) {
                if (a[i] % a[j] == 0 || a[j] % a[i] == 0)
                    Link(i, j);
            }
        }
        ans = 0;
        Dance(0);
        printf("%d\n", ans);
    }
    return 0;
}