八皇后问题，输出各解决方案。

class Solution {
public:
    int count;
    int <em>x;
    int *y;
    int index;
    bool *rows,</em>cols,<em>ltrb,</em>rtlb;
    vector&lt;vector&lt;string&gt;&gt; ans;
    vector&lt;string&gt;item;
    void SetFalse(bool *arrayin,int n) {
        for(int i = 0;i &lt; n;i++)
            arrayin[i] = false;
    }
    void Move(int row,int n) {
        for(int col = 0;col &lt; n;col++) {
            if( rows[row] != true &amp;&amp;
                cols[col] != true &amp;&amp;
                ltrb[row+col] != true&amp;&amp;
                rtlb[n-1+row-col] != true) {
                    if(row == n-1) {
                        x[index] = row;
                        y[index++] = col;<br />
                        item.clear();
                        string subitem = &quot;&quot;;
                        for(int j = 0;j &lt; n;j++) {
                            subitem.push_back('.');
                        }
                        for(int i = 0;i &lt; n;i++) {
                            item.push_back(subitem);
                        }
                        for(int i = 0;i &lt; index;i++) {
                                item[x[i]][y[i]] = 'Q';
                        }
                        ans.push_back(item);
                        index--;
                    }
                    else {
                        rows[row] = true;
                        cols[col] = true;
                        ltrb[row+col] = true;
                        rtlb[n-1+row-col] = true;
                        x[index] = row;
                        y[index++] = col;
                        Move(row+1,n);
                        index--;
                        rows[row] = false;
                        cols[col] = false;
                        ltrb[row+col] = false;
                        rtlb[n-1+row-col] = false;<br />
                    }
            }<br />
        }
    }
    vector&lt;vector&lt;string&gt; &gt; solveNQueens(int n) {<br />
        x = new int[n];
        y = new int[n];
        rows = new bool[n];//行
        SetFalse(rows,n);
        cols = new bool[n];//列
        SetFalse(cols,n);
        ltrb = new bool[n+n-1];
        SetFalse(ltrb,n+n-1);
        rtlb = new bool[n+n-1];
        SetFalse(rtlb,n+n-1);
        ans.clear();
        if(n == 1) {
            string subitem = &quot;Q&quot;;
            vector&lt;string&gt;item;
            item.clear();
            item.push_back(subitem);
            ans.push_back(item);
            return ans;
        }
        int row = 0;
        index = 0;
        for(int col = 0;col &lt; n;col++) {
            rows[row] = true;
            cols[col] = true;
            ltrb[row+col] = true;
            rtlb[n-1+row-col] = true;
            x[index] = row;
            y[index++] = col;
            Move(row+1,n);
            index--;
            rows[row] = false;
            cols[col] = false;
            ltrb[row+col] = false;
            rtlb[n-1+row-col] = false;
        }<br />
        return ans;
    }
};