DFS numerical sort

DFS: staek space: O(n) does not have the shortest

BFS: queue space: O(2^n) can find the shortest path

DFS examples and code templates 

topic description

Given an integer n, arrange the numbers 1∼n in a row, and there will be many ways to arrange them.

Now, please output all the permutation methods in lexicographical order.

Input format
A total of one line, including an integer n

Output format
Output all permutation schemes in lexicographical order, each scheme occupying one line.

Data range
1≤n≤7
input sample

3

output sample

1 2 3
1 3 2
2 1 3
2 3 1
3 1 2
3 2 1

#include<iostream>
using namespace std;
const int N = 10;

int n;
int path[N];
bool st[N];

void dfs(int u){
	if(u==n){
		for(int i=0;i<n;i++)
			printf("%d ",path[i]);
			puts("");//输出换行 
			return;
	}
	for(int i=1;i<=n;i++){
		if(!st[i]){
			path[u]=i;
			st[i]=true;//标记某个数字已经使用
			dfs(u+1);
			st[i]=false;//还原某个数字的标记
		} 
	}
}
int main(){
	cin>>n;
	dfs(0);
	return 0;
}