相交链表

推荐题解

• 相交链表
• 160. 相交链表（双指针，清晰图解）

使用 Set 哈希集合

var getIntersectionNode = function(headA, headB) {
    const visited = new Set();
    let temp = headA;
    while (temp !== null) {
        visited.add(temp);
        temp = temp.next;
    }
    temp = headB;
    while (temp !== null) {
        if (visited.has(temp)) {
            return temp;
        }
        temp = temp.next;
    }
    return null;
};

双指针

画了两个圆, 这两个圆必然在某一时刻相交

var getIntersectionNode = function(headA, headB) {
    if (headA === null || headB === null) {
        return null;
    }
    let pA = headA, pB = headB;
    while (pA !== pB) {
        pA = pA === null ? headB : pA.next;
        pB = pB === null ? headA : pB.next;
    }
    return pA;
};