C++ 统计自然数出现次数 - 高效算法实现

#include #include

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

map<int, int> countMap;
for (int i = 0; i < n; i++) {
    int num;
    cin >> num;
    countMap[num]++;
}

for (auto it = countMap.begin(); it != countMap.end(); it++) {
    cout << it->first << ' ' << it->second << endl;
}

return 0;

}