Codeforces 464B Restore Cube(暴力)

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题目链接：Codeforces 464B Restore Cube

题目大意：给定8个点坐标，对于每个点来说，可以随意交换x，y，z坐标的数值。问说8个点是否可以组成立方体。

解题思路：直接暴力枚举即可，保证一个点的坐标不变，枚举量为67，将上一层判断。

#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>using namespace std;typedef long long ll;const int maxn = 8;struct point {    ll x[3];    void input() {        for (int i = 0; i < 3; i++)            scanf("%lld", &x[i]);    }    void output() {        printf("%lld %lld %lld\n", x[0], x[1], x[2]);    }    point operator - (const point& u) {        point ret;        for (int i = 0; i < 3; i++)            ret.x[i] = x[i] - u.x[i];        return ret;    }}p[maxn+5];ll dis (point u) {    ll ret = 0;    for (int i = 0; i < 3; i++)        ret += u.x[i] * u.x[i];    return ret;}bool check (int k) {    int mv = 0;    ll d[maxn+5];    for (int i = 0; i < maxn; i++) {        if (i == k)            continue;        d[mv++] = dis(p[k] - p[i]);    }    sort(d, d + 7);    if (d[0] == 0)        return false;    if (d[0] != d[1] || d[0] != d[2])        return false;    if (d[3] != d[4] || d[3] != d[5])        return false;    if (d[0] * 2 != d[3] || d[0] * 3 != d[6])        return false;    return true;}bool judge () {    for (int i = 0; i < maxn; i++)        if (!check(i))            return false;    printf("YES\n");    for (int i = 0; i < maxn; i++)        p[i].output();    return true;}bool dfs (int d) {    if (d == maxn)        return judge();    sort(p[d].x, p[d].x + 3);    do {        if (dfs(d+1))            return true;    } while (next_permutation(p[d].x, p[d].x + 3));    return false;}int main () {    for (int i = 0; i < maxn; i++)        p[i].input();    if (!dfs(1))        printf("NO\n");    return 0;}

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