var combinationSum = function (candidates, target) {
  var result = [];
  var temp = [];
  var sum = 0;
  candidates.sort(function (a, b) {
    return a - b;
  })
  DFS(candidates, sum, 0, target, temp, result);
  return result;
};

function copy(array) {
  var result = [];
  for (var i = 0, len = array.length; i < len; i  ) {
    result.push(array[i]);
  }
  return result;
}

function DFS(candidates, sum, level, target, temp, result) {
  if (sum > target) {
    return;
  }
  if (sum == target) {
    result.push(copy(temp));
    return;
  }
  for (var i = level; i < candidates.length; i  ) {
    sum  = candidates[i];
    temp.push(candidates[i]);
    DFS(candidates, sum, i, target, temp, result);
    temp.pop();
    sum -= candidates[i];
  }
}