Algorithm/Algorithm/Solution1636.cpp at master · Pancf/Algorithm

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// Solution1636.cpp

// Algorithm

// Created by focus on 10/9/26.

#include "Solution1636.hpp"

#include <unordered_map>

std::vector<int> Solution1636::frequencySort(std::vector<int> &nums)

{

/** first version, too complex

int length = static_cast<int>(nums.size());

if (length == 1) return nums;

std::unordered_map<int, int> m;

for (auto num : nums) {

m[num] += 1;

}

std::vector<std::pair<int, int>> vec;

for (auto [k, v] : m) {

vec.push_back({k, v});

}

std::sort(vec.begin(), vec.end(), [](auto& lhs, auto& rhs) {

if (lhs.second < rhs.second) return true;

if (lhs.second == rhs.second) return lhs.first > rhs.first;

return false;

});

std::vector<int> res;

for (auto [value, freq] : vec) {

while (freq--) {

res.push_back(value);

}

return res;

// problem constraint, -100 <= nums[i] <= 100

int freq[201] = {0};

for (int num : nums) {

freq[num + 100] += 1;

}

std::sort(nums.begin(), nums.end(), [&freq](auto& lhs, auto& rhs) {

if (freq[lhs + 100] == freq[rhs + 100]) return lhs > rhs;

return freq[lhs + 100] < freq[rhs + 100];

});

return nums;

}