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32 lines
1.5 KiB
HTML
32 lines
1.5 KiB
HTML
<!DOCTYPE html>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<h1>1115. Counting Nodes in a BST (30)</h1>
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<div id="problemContent">
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<p>A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties:</p>
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<ul>
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<li>The left subtree of a node contains only nodes with keys less than or equal to the node's key.
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<li>The right subtree of a node contains only nodes with keys greater than the node's key.
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<li>Both the left and right subtrees must also be binary search trees. </li></li></li></ul>
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<p>Insert a sequence of numbers into an initially empty binary search tree. Then you are supposed to count the total number of nodes in the lowest 2 levels of the resulting tree.</p>
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<p><b>
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Input Specification:
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</b></p>
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<p>Each input file contains one test case. For each case, the first line gives a positive integer N (<=1000) which is the size of the input sequence. Then given in the next line are the N integers in [-1000 1000] which are supposed to be inserted into an initially empty binary search tree.</p>
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<p><b>
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Output Specification:
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</b></p>
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<p>For each case, print in one line the numbers of nodes in the lowest 2 levels of the resulting tree in the format:</p>
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<p>
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n1 + n2 = n
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</p>
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<p>
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where n1 is the number of nodes in the lowest level, n2 is that of the level above, and n is the sum.
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</p>
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<b>Sample Input:</b><pre>
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9
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25 30 42 16 20 20 35 -5 28
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</pre>
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<b>Sample Output:</b><pre>
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2 + 4 = 6
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</pre>
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</div> |