var addTwoNumbers = function(l1, l2) {
let pre = new ListNode(0)
cur = pre
carry = 0
while (l1 || l2) {
let x = l1 ? l1.val : 0
let y = l2 ? l2.val : 0
let sum = x + y + carry
carry = ~~(sum / 10)
cur.next = new ListNode(sum % 10)
cur = cur.next
if (l1) {
l1 = l1.next
}
if (l2) {
l2 = l2.next
}
}
if (carry === 1) {
cur.next = new ListNode(carry)
}
return pre.next
};
Runtime: 120 ms, faster than 44.26% of JavaScript online submissions for Add Two Numbers.
Memory Usage: 38.5 MB, less than 56.94% of JavaScript online submissions for Add Two Numbers.
看题解的时候发现，Math.floor()可以用~~()来代替，也不知道为啥，反正就能行。
class Solution:
def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
carry = 0
pre = cur = ListNode(0)
while l1 or l2:
v1 = l1.val if l1 else 0
v2 = l2.val if l2 else 0
_sum = v1+v2+carry
carry = _sum//10
cur.next = ListNode(_sum % 10)
cur = cur.next
if l1:
l1 = l1.next
if l2:
l2 = l2.next
if carry == 1:
cur.next = ListNode(carry)
return pre.next
Runtime: 88 ms, faster than 17.60% of Python3 online submissions for Add Two Numbers.
Memory Usage: 14.2 MB, less than 5.67% of Python3 online submissions for Add Two Numbers.
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
pre := &ListNode{0, nil}
cur := pre
carry := 0
for l1 != nil || l2 != nil {
var x, y int
if l1 != nil {
x = l1.Val
} else {
x = 0
}
if l2 != nil {
y = l2.Val
} else {
y = 0
}
sum := x + y + carry
carry = sum / 10
cur.Next = &ListNode{sum % 10, nil}
cur = cur.Next
if l1 != nil {
l1 = l1.Next
}
if l2 != nil {
l2 = l2.Next
}
}
if carry == 1 {
cur.Next = &ListNode{carry, nil}
}
return pre.Next
}
Runtime: 16 ms, faster than 20.80% of Go online submissions for Add Two Numbers.
Memory Usage: 5 MB, less than 51.22% of Go online submissions for Add Two Numbers.
go有个更加简洁的做法
不需要另外设立carry，只需全局留sum，carry值就是其除以10
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
pre := &ListNode{0, nil}
cur := pre
var sum int
for l1 != nil || l2 != nil {
sum /= 10
if l1 != nil {
sum += l1.Val
l1 = l1.Next
}
if l2 != nil {
sum += l2.Val
l2 = l2.Next
}
cur.Next = &ListNode{sum % 10, nil}
cur = cur.Next
}
if sum/10 == 1 {
cur.Next = &ListNode{1, nil}
}
return pre.Next
}
Runtime: 8 ms, faster than 89.62% of Go online submissions for Add Two Numbers.
Memory Usage: 4.9 MB, less than 85.37% of Go online submissions for Add Two Numbers.