LeetCode day15 2014/11/3

42. Add Two Numbers

LinkList 必看题！

dummyHead

43. Add Binary

carry = a.charAt(p1) - '0';

res = String.valueOf(carry%2) + res;

44. Merge K Sorted Lists

跳过

45. Rotated List

K 可能大于 linked list 的长度，n=n%len;