O(n)^6

#include <string.h>
#include "doublewordsquare.h"
#include "cs136.h"

bool word_grid_possible(char *words[8]){
  // checking row
  char ans[4];
  int correct = 0;
  int used[3] = {-1, -1, -1};

  for (int i = 0; i < 8; ++i) {
    for (int j = 0; j < 8; ++j) {
      if (j == i) {
        continue;
      } else if (words[i][1] == words[j][0]) {
        for (int k = 0; k < 8; ++k) {
          if (k == i || k == j) {
            continue;
          } else if (words[i][2] == words[k][0]){
            for (int l = 0; l < 8; ++l) {
              if (l == i || l == j || l == k) {
                continue;
              } else if (words[i][3] == words[l][0]) {
                for (int m = 0; m < 4; ++m) {
                  ans[0] = words[i][m];
                  ans[1] = words[j][m];
                  ans[2] = words[k][m];
                  ans[3] = words[l][m];

                  for (int n = 0; n < 8; ++n) {
                    if (n == i || n == j || n == k || n == l || n == used[0] || n == used[1] || n == used[2]) {
                      continue;
                    } else if (strcmp(ans, words[n]) && correct == 3) {
                      return true;
                    } else if (strcmp(ans, words[n])) {
                      ++correct;
                      used[m] = n;
                      break;
                    }
                  }
                  if (correct != m+1) {
                    return false;
                  }
                }
              }
            }
          }
        }
      }
    }
  }
  return false;
}