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 
   
     #include 
    
      #include 
     
       #include 
      
        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; }