44 lines
1023 B
Java
44 lines
1023 B
Java
public static LinkedListNode intersect(LinkedListNode a, LinkedListNode b){
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if (a == null || b == null) return null;
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LinkedListNode a_head = a;
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LinkedListNode b_head = b;
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int a_len, b_len = 1;
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// iterate through A
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while (a_head.next != null){
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a_head = a_head.next;
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a_len += 1;
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}
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// iterate through B
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while (b_head.next != null){
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b_head = b_head.next;
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b_len += 1;
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}
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// last node inequal, return null
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if (a_head != b_head) return null; // changed from before
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// compare lengths, adjust node
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if (a_len == 1 or b_len == 1) return a_head;
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// improved
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LinkedListNode shorter = a_len < b_len ? a : b;
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LinkedListNode longer = b_len < a_len ? b : a;
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int diff = Math.abs(a_len - b_len);
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while(k > 0 && longer != null){
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longer = longer.next;
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k--;
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}
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// there's intersection
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while(shorter != longer){
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shorter = shorter.next;
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longer = longer.next;
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}
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return shorter;
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} |