C++ 统计自然数出现次数并排序输出

#include #include

int main() { int n; cin >> n;

map<int, int> countMap;
vector<int> nums;

for (int i = 0; i < n; i++) {
    int num;
    cin >> num;
    countMap[num]++;
    if (countMap[num] == 1) {
        nums.push_back(num);
    }
}

for (int num : nums) {
    cout << num << ' ' << countMap[num] << endl;
}

return 0;

}