Permutations .cpp

#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
  bool isVisited[200];
  void DFS(vector<vector<int> >&result,  vector<int> &temp, vector<int> &num, int index) {
    if(temp.size() == num.size() ){
	result.push_back(temp);
	return;
      }

    for(size_t i=0; i < num.size(); i++){
      if( !isVisited[i]) {
	temp.push_back(num[i]);
	isVisited[i] = 1;    // mark the currrent num
	DFS(result, temp, num,i+1);
	isVisited[i] =  0;  // restore
	temp.pop_back();
      }
    }
  }
  vector<vector<int> > permute(vector<int> &num) {
    vector<vector<int> > all;
    vector<int> temp;
    memset(isVisited,0,sizeof(isVisited));
    DFS(all,temp,num,0);
    return all;        
  }
};

int main(void)
{
  Solution s;
  int arr[] = {1,2,3};
  vector<int> numbers;
  for(int i=0; i<sizeof(arr)/sizeof(int);i++)
    numbers.push_back(arr[i]);
  vector<vector<int> > result = s.permute(numbers);
  getchar();
  return 0;
}