comefrom: <awangdev>Permutation Sequence_2.java
code: public String getPermutation(int n, int k) {
          if (n <= 0 || k <= 0) {
          	return "";
          }
          ArrayList<Integer> nums = new ArrayList<Integer>();
          for (int i = 1; i <= n; i++) {
          	nums.add(i);
          }
  
          int frontInd = 0;
          for (; frontInd < nums.size(); frontInd++) {
  	        int factorio = 1;
  	    	for (int i = 1; i < n; i++) {
  	    		factorio = factorio * i;
  	    	}
  	    	int startInd = frontInd;
  	    	int numPermute = factorio;
  	    	while (numPermute < k) {
  	    		numPermute += factorio;
  	    		startInd++;
  	    	}
  
  	    	if (startInd != frontInd) {
  	    		int temp = nums.get(startInd);
  	    		nums.remove(startInd);
  	    		nums.add(frontInd, temp);
  		  		k = k - numPermute;
  		  		n--;
  	        }
  	    }
  	    StringBuffer sb = new StringBuffer();
        	for (int num : nums) {
        		sb.append(num);
        	}
          return sb.toString();
      }
masked: public String var_0 ( int var_1 , int var_2 ) {
    if ( var_1 <= 0 || var_2 <= 0 ) {
      return "" ;
    }
    ArrayList < Integer > var_7 = new ArrayList < Integer > ( ) ;
    for ( int var_9 = 1 ;
    var_9 <= var_1 ;
    var_9 ++ ) {
      var_7 . add ( var_9 ) ;
    }
    int var_11 = 0 ;
    for ( ;
    var_11 < var_7 . size ( ) ;
    var_11 ++ ) {
      int var_13 = 1 ;
      for ( int var_9 = 1 ;
      var_9 < var_1 ;
      var_9 ++ ) {
        var_13 = var_13 * var_9 ;
      }
      int var_14 = var_11 ;
      int var_15 = var_13 ;
      while ( var_15 < var_2 ) {
        var_15 += var_13 ;
        var_14 ++ ;
      }
      if ( var_14 != var_11 ) {
        int var_17 = var_7 . get ( var_14 ) ;
        var_7 . remove ( var_14 ) ;
        var_7 . add ( var_11 , var_17 ) ;
        var_2 = var_2 - var_15 ;
        var_1 -- ;
      }
    }
    StringBuffer var_20 = new StringBuffer ( ) ;
    for ( int var_21 : var_7 ) {
      var_20 . append ( var_21 ) ;
    }
    return var_20 . toString ( ) ;
  }
  