Leetcode 51. N-queens

The n-queens Puzzle is the problem of placing N Queens on anxn chessboard such that n o The Queens attack each of the 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 Indic Ate a queen and an empty space respectively.

For example,
There exist-distinct solutions to the 4-queens puzzle:

[ [". Q.. ",  //solution 1  " ... Q ",  " Q ... ",".  . Q. "], ["]. Q. ",  //Solution 2  " Q ... ",  " ... Q ",  ". Q.. "]

#include <iostream> #include <vector> #include <string>using namespace std;vector<string>  Queenslayout (vector< vector<int> >& chessboard) {vector<string> res;    for (int i = 0; i < chessboard.size (); ++i) {String tmp = "";      for (int j = 0; J < chessboard[i].size (); ++j) {if (chessboard[i][j] = = 1) TMP = tmp + "Q";    else tmp + = ".";  } res.push_back (TMP); } return res;  BOOL Checkrows (vector< vector<int> >& chessboard, int i, int dep) {int tmp = 0;  Just need to check until the dep-th column for (int k = 0; k < dep; ++k) {tmp + = Chessboard[i][k]; } return TMP = = 0;}  BOOL Checkcols (vector< vector<int> >& chessboard, int i, int dep) {int tmp = 0;  Just need to check until the i-th row for (int k = 0; k < i; ++k) {tmp + = CHESSBOARD[K][DEP]; } return TMP = = 0;} BOOL Checkdiag (vector< vector<int> >& chessboard, int i, int dep) {  int tmp = 0;&NBSp int row = i, col = dep; //Check left-up diag.  while (row >= 0 && col >= 0) {    t MP + = chessboard[row][col];    row--;    col--; }  if (tmp > 1) return false;    TMP = 0;  row = i, col = dep; //Check Left-down diag.  while (Row < Chessboard.size () && Col >= 0) {    tmp + = chessboard[row][col];    row++;    col--; }   return TMP = = 1;}  BOOL Noconflict (vector< vector<int> >& chessboard, int i, int dep) {  return checkrows (chessboard, I, DEP) && Checkcols (chessboard, I, DEP) && Checkdiag (chessboard, I, DEP);} void Solvequeens (vector< vector<int> >& chessboard, vector< vector<string> >& res, int DEP) {  if (dep = = Chessboard.size ()) {    vector<string> tmp = queenslayout (chessboard);     res.push_back (TMP);    return; }  for (int i = 0; i < chessboard.size (); ++i) {    CHESSBOARD[I][DEP] = 1;    if (noconflict (chessboard, I, DEP)) {      Solvequeens (ChessBoard, Res, dep+1);   }    CHESSBOARD[I][DEP] = 0; }}vector< vector<string> > Solvequeens (int n) {  vector< vector<int> > Chessboard (n, vector<int> (n, 0));  vector< vector<string> > res;  solvequeens (Chessboard, res, 0);  return res; int main (void) {  vector< vector<string> > Res = solvequeens (4);  for (int i = 0; i < res.size ();  ++i) {    for (int j = 0; J < res[i].size (); ++j) {      cout << Res[i][j] << endl;   }    cout << endl; }}

Leetcode 51. N-queens