Google puzzle

1. Solve this cryptic equation， realizing of course that values for M and E
could be interchanged. No leading zeros are allowed.

WWWDOT - GOOGLE = DOTCOM

虽然找到O+L = O 或者 O - 9 -1 = O的规律，但是还是认为自己大脑再行穷举路径太多了。所以重用了自己过去的代码解决了。

//
验证函数

bool IsCorrent( int dest)
… {

int wwwdot = dest[ 0 ] ( 100000 + 10000 + 1000 ) + dest[
1 ] 100 + dest[ 2 ] 10 + dest[ 3 ];

int google = dest[ 4 ] ( 100000 + 100 ) + dest[ 2 ] (
10000 + 1000 ) + dest[ 5 ] 10 + dest[ 6 ];

int dotcom = dest[ 1 ] 100000 + dest[ 2 ] ( 10000 + 10
) + dest[ 3 ] 1000 + dest[ 7 ] 100 + dest[ 8 ];

if (wwwdot - google == dotcom)
… {

return true ;
}

else
… {

return false ;
}
}

//
求子集函数

void All( int src, int currentIndex, int len, int dest, int
num)
… {

if (currentIndex == len)

return ;

dest[num ++ ] = src[currentIndex ++ ];

if (num == 9 )
… {

Perm(dest, 0 , 8 , 9 );
}

All(src,currentIndex,len,dest,num);

All(src,currentIndex,len,dest,num - 1 );
}


//
求排列函数

void Perm( int src, int current, int lesslen, int len)
… {

if (current == lesslen)
… {

if (IsCorrent(src))
… {

for ( int i = 0 ; i < len; i ++ )
… {

cout << src[i] << “ “ ;
}

cout << endl;
}
}


for ( int i = current; i < len; i ++ )
… {

swap(src[i],src[current]);

Perm(src,current + 1 ,lesslen,len);

swap(src[i],src[current]);
}

}

最后：

WDOTGLECM分别为7 5 8 9 1 0 6 4 3或7 5 8 9 1 0 3 4 6因为E和M可以互换，所以正解…..