分析

程式碼

/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var addTwoNumbers=function(l1, l2) {
    let dummyHead = new ListNode(0), node=dummyHead;
    let overflow=0, a, b, c, val;
    while(l1!==null || l2!==null) {
        a=(l1===null)?0:l1.val;
        b=(l2===null)?0:l2.val;
        c=a+b+overflow;
        val=c%10;
        overflow=Math.floor(c/10);
        node.next=new ListNode(val);
        node=node.next;
        if(l1!==null) l1=l1.next;
        if(l2!==null) l2=l2.next;
    }
    if(overflow!==0) {
        node.next=new ListNode(overflow);
    }
    return dummyHead.next;
}