力扣第二题俩数相加-可以直接运行

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import java.util.ArrayList;

/**
 * @author huang.
 * @version 1.0
 * @date 2020-5-7 15:02
 */
class LNode {
    int var;
    LNode next;
　　
    public LNode(int x) {
        var = x;
        next = null;
    }

    public static void main(String[] args) {
        int a[] = {2, 4, 3};//{6};
        int b[] = {5, 6, 4};//{7,7,7};
        LNode l1 = madeLNode(a);
        LNode l2 = madeLNode(b);
        System.out.println(toList(l1));
        System.out.println(toList(l2));
        System.out.println("-----------------------------------------------");
        LNode node = addTwoNumbers(l1, l2);
        System.out.println(toList(node));
    }

    private static LNode addTwoNumbers(LNode l1, LNode l2) {
        LNode head = new LNode(0);
        LNode p = l1, q = l2 ,curr = head;
        //进位
        int carry = 0;
        while (p != null || q != null) {
            int x = (p != null) ? p.var : 0;
            int y = (q != null) ? q.var : 0;
            int sum = x+y+carry;
            carry = sum/10;
            int value = sum % 10;
            curr.next = new LNode(value);
            curr = curr.next;
            if (q!= null) q =q.next;
            if (p!= null) p = p.next;
        }
        //例如7+8问题,需要进位
        if (carry>0 ){
           curr.next =  new LNode(1);
        }
        return head.next;
    }

    private static LNode madeLNode(int[] a) {
        LNode node = new LNode(a[0]);
        LNode head = node;

        for (int i = 1; i < a.length; i++) {
            LNode nodeList = new LNode(a[i]);
            node.next = nodeList;
            node = node.next;
        }
        return head;
    }

    private static ArrayList<Integer> toList(LNode node) {
        ArrayList<Integer> list = new ArrayList<>();
        while (node != null) {
            list.add(node.var);
            node = node.next;
        }
        return list;
    }
}