52 lines
2.0 KiB
C++
52 lines
2.0 KiB
C++
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// Source : https://leetcode.com/problems/h_index/
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// Author : Calinescu Valentin
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// Date : 2015-10-22
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/***************************************************************************************
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*
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* Given an array of citations (each citation is a non-negative integer) of a
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* researcher, write a function to compute the researcher's h-index.
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*
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* According to the definition of h-index on Wikipedia: "A scientist has index h if h of
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* his/her N papers have at least h citations each, and the other N − h papers have no
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* more than h citations each."
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*
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* For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5
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* papers in total and each of them had received 3, 0, 6, 1, 5 citations respectively.
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* Since the researcher has 3 papers with at least 3 citations each and the remaining
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* two with no more than 3 citations each, his h-index is 3.
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*
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* Note: If there are several possible values for h, the maximum one is taken as the
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* h-index.
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*
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***************************************************************************************/
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/*
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* Solutions
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* =========
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*
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* A simple solution would be to sort the vector and then run through it starting with
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* the last element. At every step we need to check whether this element is not less than
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* the remaining number of elements bigger than it(including itself) and all the values of
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* the other elements smaller than it are not more than that number. The h_index is this
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* number of elements bigger than it(including itself).
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*
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* Time Complexity: O(N log N)
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* Space Complexity: O(1)
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*
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*/
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#include <algorithm>
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class Solution {
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public:
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int hIndex(vector<int>& citations) {
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sort(citations.begin(), citations.end());
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int h_index = 0;
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for(int i = citations.size() - 1; i >= 0; i--)
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if(citations[i] >= citations.size() - i && (i - 1 < 0 || citations[i - 1] <= citations.size() - i))
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h_index = citations.size() - i;
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return h_index;
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}
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};
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