40 lines
1023 B
C++
40 lines
1023 B
C++
#include <unordered_set>
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#include <vector>
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#include <iostream>
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/**
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* 523. Continuous Subarray Sum
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*
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* Given an integer array nums and an integer k, return true if nums has a continuous subarray of size at least two whose elements sum up to a multiple of k, or false otherwise.
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* An integer x is a multiple of k if there exists an integer n such that x = n * k. 0 is always a multiple of k.
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*/
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class Solution {
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public:
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static bool checkSubarraySum(const std::vector<int>& nums, int k) {
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int sum = nums[0] % k, n = nums.size(), prev = 0;
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if (n < 2)
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return false;
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if (k == 1)
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return true;
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if (n == 2)
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return (nums[0] + nums[1]) % k == 0;
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std::unordered_set<int> s{0, nums[0] % k};
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for (int i = 1; i < n; ++i) {
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if (!(nums[i] % k) && !(nums[i - 1] % k))
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return true;
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prev = sum;
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sum = (sum + nums[i]) % k;
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if (s.count(sum) && prev != sum)
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return true;
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s.insert(sum);
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}
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return false;
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}
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};
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int main() {
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std::cout << Solution::checkSubarraySum({1,2,12}, 6);
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return 0;
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}
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