[Leetcode] N Queens I,II

http://leetcode.com/onlinejudge#question_51

The n-queens puzzle is the problem of placing n queens
on an n×n chessboard
such that no two queens attack each other.



Given an integer n, return all distinct solutions to the n-queens
puzzle.

Each solution contains a distinct board configuration of the n-queens' placement, where

'Q'

and

'.'

both
indicate a queen and an empty space respectively.

For example,

There exist two distinct solutions to the 4-queens puzzle:

[
[".Q..",  // Solution 1
"...Q",
"Q...",
"..Q."],

["..Q.",  // Solution 2
"Q...",
"...Q",
".Q.."]
]

class Solution {
public:
bool check(int row, int* place)
{
for(int i=0;i<row;i++)
{
int diff = abs(place[row]-place[i]);
if(diff == 0 || diff == row - i) return false;
}
return true;
}

void placeQueens(int row, int n, int &count, int* place,
vector<vector<string> > &result)
{
if(row==n)
//indicates success
{
vector<string> tmp;
count++;
for(int i=0;i<n;i++)
{
string str(n,'.');
str[place[i]] = 'Q';
tmp.push_back(str);
}
result.push_back(tmp);
return;
}
for(int i=0;i<n;i++)
{
place[row] = i;
if(check(row,place))
{
placeQueens(row+1,n,count,place,result);
}
}
}

int totalNQueens(int n) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
vector<vector<string> > result;
int count = 0;
int* place = new int
;
placeQueens(0,n,count,place,result);
return count;
}
};