题解 | #八皇后#

传一个指针进去捕捉终点

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cstring>

using namespace std;

//个人思路：逐行地放皇后 

int queen[8] = {
	-1,-1,-1,-1,-1,-1,-1,-1
}; 

void DFS(int b, int row, int col, int* sum){
	for(int i=0; i<8; i++){
		if(i == row || queen[i] == -1){
			continue;
		}else if(queen[i]==col || abs(queen[i]-col)==abs(i-row)){
			return;
		}
	}//通过这个考验，则本次放皇后是合法的
	queen[row] = col;
	if(row == 7){
		(*sum)++;
		if(*sum == b){
			for(int i=0; i<8; i++){
				printf("%d",queen[i]+1);
			}
			printf("\n");
		}
		
	}else{
		for(int i=0; i<8; i++){
			DFS(b, row+1, i, sum);
			if(*sum == b){
				return;
			}
		}
	}
	queen[row] = -1;
	return;
}

int main(){
	int b;
	int sum = 0;
	while(scanf("%d",&b) != EOF){
		for(int i=0; i<8; i++){
			DFS(b,0,i,&sum);
		}
		sum = 0;
		memset(queen, -1, sizeof(queen));
	}
	return 0;
}