UV 12326 & HDU 4092-yummy triangular pizza (hash + Table hitting)

Link to the question: Ultraviolet A 12326 & HDU 4092 yummy triangular pizza

N indicates that N is used to form a graph. The number of different triangles, rotation, and image can be considered the same.

Solution: It is clever to refer to other people's ideas, mainly to build three-dimensional coordinate axes.

Triangle X + Y + z = 0
Inverted triangle X + Y + z =0

In this way, the images are added one by one from the triangle with the initial loading state 0 0, and the image is rotated each time to determine whether there are duplicates.
Each time a repeat is determined, a triangle in the enumeration graph is processed as the origin, and the hash value is generated. N is considered to be multiple 16 bits, so the range of X, Y, and Z is not greater than 8.

#include <cstdio>#include <cstring>#include <set>#include <algorithm>using namespace std;const int maxn = 16;struct Trian {    int x, y, z;    Trian () {};    Trian (int x, int y, int z) {        this->x = x;        this->y = y;        this->z = z;    }    Trian add (int type) {        int mv = (x+y+z == 0 ? 1 : -1);        if (type == 0)            return Trian(x, y+mv, z+mv);        else if (type == 1)            return Trian(x+mv, y, z+mv);        else            return Trian(x+mv, y+mv, z);    }    void rotate () {        int tmp = x;        x = y;        y = z;        z = tmp;    }    void overturn () {        x = 1 - x;        y = 1 - y;        z = -z;    }    void move (int x, int y, int z) {        this->x += x;        this->y += y;        this->z += z;    }};bool operator == (const Trian& a, const Trian& b) {    return a.x == b.x && a.y == b.y && a.z == b.z;}bool operator < (const Trian& a, const Trian& b) {    if (a.x != b.x)        return a.x < b.x;    else if (a.y != b.y)        return a.y < b.y;    else        return a.z < b.z;}struct Hash {    int cnt, key[maxn+5];};bool operator < (const Hash& a, const Hash& b) {    if (a.cnt != b.cnt)        return a.cnt < b.cnt;    for (int i = 0; i < a.cnt; i++)        if (a.key[i] != b.key[i])            return a.key[i] < b.key[i];    return false;}struct Pizz {    int cnt;    Trian arr[maxn+5];    Pizz () { cnt = 0; }    bool add (const Trian& u) {        for (int i = 0; i < cnt; i++)            if (arr[i] == u)                return false;        arr[cnt++] = u;        return true;    }    void remove () { cnt--; }    Hash getKey () {        Hash u;        u.cnt = cnt;        for (int i = 0; i < cnt; i++) {            u.key[i] = arr[i].x + 8;            u.key[i] <<= 4;            u.key[i] += arr[i].y + 8;            u.key[i] <<= 4;            u.key[i] += arr[i].z + 8;        }        return u;    }};set<Hash> vis;int ans[maxn+5] = {0};bool find (Pizz v) {    for (int i = 0; i < 3; i++) {        sort(v.arr, v.arr+v.cnt);        if (vis.find(v.getKey()) != vis.end())            return true;        for (int j = 0; j < v.cnt; j++)            v.arr[j].rotate();    }    return false;}bool search (Pizz u) {    for (int i = 0; i < u.cnt; i++) {        int x = u.arr[i].x;        int y = u.arr[i].y;        int z = u.arr[i].z;        Pizz v = u;        if (x + y + z == 0) {            for (int j = 0; j < v.cnt; j++)                v.arr[j].move(-x, -y, -z);            if (find(v))                return true;        } else {            for (int j = 0; j < v.cnt; j++) {                v.arr[j].overturn();                v.arr[j].move(x-1, y-1, z);            }            if (find(v))                return true;        }    }    return false;}void insert (Pizz u) {    for (int i = 0; i < 3; i++) {        sort(u.arr, u.arr+u.cnt);            vis.insert(u.getKey());        for (int j = 0; j < u.cnt; j++)            u.arr[j].rotate();    }}void dfs (Pizz u) {    if (u.cnt == maxn+1)        return;    if (search(u))        return;    insert(u);    ans[u.cnt]++;    for (int i = 0; i < u.cnt; i++) {        for (int j = 0; j < 3; j++) {            Trian v = u.arr[i].add(j);            if (u.add(v)) {                dfs(u);                u.remove();            }        }    }}int rec[maxn+5] = {0, 1, 1, 1, 4, 6, 19, 43, 120, 307, 866, 2336, 6588, 18373, 52119, 147700, 422016};int main () {    /*    Pizz u;    u.add(Trian(0, 0, 0));    dfs(u);    for (int i = 0; i <= maxn; i++)        printf("%d\n", ans[i]);    */    int cas, n;    scanf("%d", &cas);    for (int i = 1; i <= cas; i++) {        scanf("%d", &n);        printf("Case #%d: %d\n", i, rec[n]);    }    return 0;}