Valid Pattern Lock(dfs + 暴力）

Valid Pattern LockTime Limit: 2 Seconds Memory Limit: 65536 KB
Pattern lock security is generally used in Android handsets instead of a password. The pattern lock can be set by joining points on a 3 × 3 matrix in a chosen order. The points of the matrix are registered in a numbered order starting with 1 in the upper left corner and ending with 9 in the bottom right corner.

#include<stdio.h>
#include<string.h>
#include<algorithm>
int T ;
int n , a[15] ;
int b[15] ;
bool vis[15] ;
bool blog[15] ;
bool flag = 0 ;
int cnt = 0 ;
int ans[362880 + 10][11] ;

bool judge (int sx , int ex)
{
if (sx == 1 && ex == 3 || sx == 3 && ex == 1) {
if (blog[2]) return true ;
return false ;
}
else if (sx == 1 && ex == 7 || sx == 7 && ex == 1) {
if (blog[4]) return true ;
return false ;
}
else if (sx == 3 && ex == 9 || sx == 9 && ex == 3) {
if (blog[6]) return true ;
return false ;
}
else if (sx == 7 && ex == 9 || sx == 9 && ex == 7) {
if (blog[8]) return true ;
return false ;
}
else if (sx == 2 && ex == 8 || sx == 8 && ex == 2) {
if (blog[5]) return true ;
return false ;
}
else if (sx == 4 && ex == 6 || sx == 6 && ex == 4) {
if (blog[5]) return true ;
return false ;
}
else if (sx == 1 && ex == 9 || sx == 9 && ex == 1) {
if (blog[5]) return true ;
return false ;
}
else if (sx == 3 && ex == 7 || sx == 7 && ex == 3) {
if (blog[5]) return true ;
return false ;
}
return true ;
}

void dfs (int deep)
{
if (deep == n + 1 ) {
memset (blog , 0 , sizeof(blog)) ;
flag = 1 ;
blog[b[1]] = 1 ;
for (int i = 2 ; i <= n && flag; i++) {
flag = judge (b[i - 1] , b[i]) ;
blog[b[i]] = 1 ;
}
if (flag) {
for (int i = 1 ; i <= n ; i++) {
ans[cnt][i] = b[i] ;
}
cnt ++ ;
}
/*  for (int i = 1 ; i <= n ; i++) {
printf ("%d " , a[i]);
}
puts ("") ;*/
return ;
}
for (int i = 1 ; i <= n ; i++) {
if (vis[a[i]] == 0) {
vis[a[i]] = 1 ;
b[deep] = a[i] ;
dfs (deep + 1) ;
vis[a[i]] = 0 ;
}
}
}

int main ()
{
//freopen ("a.txt" , "r" , stdin ) ;
scanf ("%d" , &T) ;
while (T --) {
scanf ("%d" , &n) ;
for (int i = 1 ; i <= n ; i++) {
scanf ("%d" , &a[i]);
}
cnt = 0 ;
std::sort (a + 1 , a + n + 1 ) ;
for (int i = 1 ; i <= n ; i++) {
memset (vis , 0 , sizeof(vis)) ;
vis[a[i]] = 1 ;
b[1] = a[i] ;
dfs (2) ;
}
printf ("%d\n" , cnt) ;
for (int i = 0 ; i < cnt ; i++) {
for (int j = 1 ; j <= n ; j++) {
printf ("%d%c" , ans[i][j] , j == n ? '\n' : ' ') ;
}
}
}
return 0 ;
}

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