text: var getIntersectionNode = function (headA, headB) {
    let ha = headA,
      hb = headB;
    while (ha != hb) {
      ha = ha ? ha.next : headB;
      hb = hb ? hb.next : headA;
    }
    return ha;
  };
  
  // 暴力法
  var getIntersectionNode = function (headA, headB) {
    let ha = headA;
    while (ha) {
      let hb = headB;
      while (hb) {
        if (ha == hb) return ha;
        hb = hb.next;
      }
      ha = ha.next;
    }
  };
  
  // 哈希表
  var getIntersectionNode = function (headA, headB) {
    let set = new Set(),
      ha = headA,
      hb = headB;
    while (ha) {
      set.add(ha);
      ha = ha.next;
    }
    while (hb) {
      if (set.has(hb)) return hb;
      hb = hb.next;
    }
  };
  