LeetCode 51. N皇后

LeetCode 51. N皇后

开始主要错误是从位置1开始放的，vector下标从0开始emmm

vector和string的构造函数使用

class Solution {
private:
    int book[3][1000];
    vector<vector<string>> ans;
    
    void queen(int n,int cur,vector<int> &temp)
    {
        if(cur==n)
        {
            ans.push_back(combineAns(n,temp));
            return;
        }
        for(int i=0;i<n;++i)
        {
            if(!book[0][i]&&!book[1][cur+i]&&!book[2][cur-i+n])
            {
                temp.push_back(i);
                book[0][i]=book[1][cur+i]=book[2][cur-i+n]=1;
                queen(n,cur+1,temp);
                book[0][i]=book[1][cur+i]=book[2][cur-i+n]=0;
                temp.pop_back();
            }
        }
    }
    
    vector<string> combineAns(int n,vector<int> &a)
    {
        vector<string> now(n,string(n,'.'));
        for(int i=0;i<n;++i)
            now[i][a[i]]='Q';
        return now;
    }
    
public:
    vector<vector<string>> solveNQueens(int n) {
        ans.clear();
        memset(book,0,sizeof(book));
        vector<int> temp;
        queen(n,0,temp);
        return ans;
    }
};