25 lines
710 B
C++
25 lines
710 B
C++
#include <unordered_set>
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#include <vector>
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#include <algorithm>
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/**
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* 2367. Number of Arithmetic Triplets
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*
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* You are given a 0-indexed, strictly increasing integer array nums and a positive integer diff. A triplet (i, j, k) is an arithmetic triplet if the following conditions are met:
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*
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* i < j < k,
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* nums[j] - nums[i] == diff, and
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* nums[k] - nums[j] == diff.
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* Return the number of unique arithmetic triplets.
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*/
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class Solution {
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public:
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static int arithmeticTriplets(const std::vector<int>& nums, int diff) {
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std::unordered_set<int> s(nums.begin(), nums.end());
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return std::count_if(nums.begin(), nums.end(), [&](int x) {
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return s.count(x + diff) && s.count(x + 2 * diff);
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});
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}
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};
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