function minfree(xs) {
  var _a = 0;
  var _n = List.length(xs);
  var _xs = xs;
  while(true) {
    var xs$1 = _xs;
    var n = _n;
    var a = _a;
    var b = (a + 1 | 0) + (n / 2 | 0) | 0;
    var match = List.partition((function(b){
        return function (x) {
          return +(x < b);
        }
        }(b)), xs$1);
    var us = match[0];
    var m = List.length(us);
    if (n) {
      if (m === (b - a | 0)) {
        _xs = match[1];
        _n = n - m | 0;
        _a = b;
        continue ;

      } else {
        _xs = us;
        _n = m;
        continue ;

      }
    } else {
      return a;
    }
  };
}