/**
树的3中常见搜索方式
1.二叉树方式（每一层只有0和1）
2.满m叉树（每一层都有0 到m - 1）
3.子集树，也称为全排列树
*/
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
using namespace std;
const int M = 20;
int n, m;
int ans[M];
//二叉树
void dfs_two(int cur){
if(cur == n){
for(int i = 0; i < n; i++){
cout << ans[i] << " ";
}
cout << endl;
return;
}
ans[cur] = 1;
dfs_two(cur + 1);
ans[cur] = 0;
dfs_two(cur + 1);
}
//m叉树
void dfs_m(int cur){
if(cur == n){
for(int i = 0; i < n; i++){
cout << ans[i] << " ";
}
cout << endl;
return ;
}
for(int i =0; i < n; i++){
ans[cur] = i;
dfs_m(cur + 1);
}
}
bool vis[M];
//子集树
void dfs_sub(int cur){
if(cur == n){
for(int i = 0; i < n; i++){
cout << ans[i] << " ";
}
cout << endl;
return;
}
for(int i = 0; i < n; i++){
if(false == vis[i]){
vis[i] = true;
ans[cur] = i;
dfs_sub(cur + 1);
vis[i] = false;
}
}
}
int main(){
n = 5;
memset(ans, -1, sizeof(ans));
memset(vis, false, sizeof(vis));
dfs_two(0);//二叉树搜索
dfs_m(0);//满m叉树搜索
dfs_sub(0);//子集树搜索
return 0;
}
