题解 | #八皇后#

#include<iostream>
#include<vector>
using namespace std;
const int N = 20;
int b;
bool col[N],dg[N],udg[N];
vector<int>res;

void dfs(int n,int u,int s) {
	if(u==n) {
		res.push_back(s);
		return;
	}
	for(int i=0; i<n; i++) {
		if(!col[i] && !dg[u+i] && !udg[n-i+u]) {
			col[i] = dg[u+i] = udg[n-i+u] = true;
			dfs(n,u+1,i+1+10*s);
			col[i] = dg[u+i] = udg[n-i+u] = false;
		}
	}
}

int main() {
	// freopen("input.txt","r",stdin);
	dfs(8,0,0);
	while(~scanf("%d",&b)) {
		printf("%d\n",res[b-1]);
	}
	return 0;
}