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#include "header.hpp"
#include <unordered_map>
class Solution {
public:
static int maxOperations(std::vector<int> &nums, int k) {
int result = 0;
std::unordered_map<int, int> dict;
for (auto &iter : nums) {
if (dict.find(iter) != dict.end()) {
dict[iter]++;
} else {
dict.insert(std::make_pair(iter, 1));
}
}
for (auto &iter : dict) {
if (k > iter.first) {
if (dict.find(k - iter.first) != dict.end()) {
if (k - iter.first == iter.first) {
result = result + int(iter.second / 2);
} else {
auto dec = std::min(dict[iter.first], dict[k - iter.first]);
result = result + dec;
dict[iter.first] -= dec;
dict[k - iter.first] -= dec;
}
}
}
}
return result;
}
};
int main(int argc, char **argv) {
std::vector<int> num1 = {1, 2, 3, 4};
std::vector<int> num2 = {3, 1, 3, 4, 3};
std::vector<int> num3 = {2, 2, 2, 3, 1, 1, 4, 1};
std::vector<int> num4 = {3, 5, 1, 5};
std::vector<int> num5 = {2, 5, 4, 4, 1, 3, 4, 4, 1, 4,
4, 1, 2, 1, 2, 2, 3, 2, 4, 2};
std::cout << Solution::maxOperations(num1, 5) << std::endl; // 2
std::cout << Solution::maxOperations(num2, 6) << std::endl; // 1
std::cout << Solution::maxOperations(num3, 4) << std::endl; // 2
std::cout << Solution::maxOperations(num4, 2) << std::endl; // 0
std::cout << Solution::maxOperations(num5, 3) << std::endl; // 4
return 0;
}
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