四皇后问题代码注析 数据结构与算法分析 张琨

1、关键点就在注释那

#ifndef SHH_H_
#define SHH_H_
#include"iostream"

using namespace std;

class Backtracking
{
public:
	Backtracking(){ n = 4; C = new int[n]; count = 0; };
	void Trial(int i);
	void Print();
	int Check(int i);

private:
	int *C;
	int n;
	int count;

};

void Backtracking::Trial(int i)
{
	if (i==n)                               //有四个打印结果
	{
		Print();
	}
	else
	{
		for (int j = 0; j < n; j++)
		{
			C[i] = j;
			if (Check(i))
			{
				Trial(i + 1);              //递归
			}
		}
	}
}

int Backtracking::Check(int i)
{
	for (int j = 0; j < i; j++)                                            
	{
		if (C[i] == C[j] || i - C[i] == j - C[j] || i + C[i] == j + C[j])  //列， 左对角线，右对角线。
			return 0;
	}
	return 1;
}

void Backtracking::Print()
{
	cout << "解" << ++count << endl;
	int i, j;
	for ( i = 0; i < n; i++) 
	{
		for (j = 0; j < n; j++)
		{
			if (j==C[i])
			{
				cout << '*';
			}
			else
			{
				cout << '-';
			}
			
		}cout << endl;
	}cout << endl;
}


#endif

2 主程序

#include "shh.h"
#include "iostream"


int main()
{
	Backtracking T;
	T.Trial(0);
	return 0;
}