leetcode-master/problems/kamacoder/完美数.md

```CPP 
#include <iostream>
#include <vector>
using namespace std;
int countOnes(long long num) {
    int zeroCount = 0;
    while (num > 0) {
        if (num % 10 != 0) {  // 检查最低位是否为0
            zeroCount++;
        }
        num /= 10;  // 移除最低位
    }
    return zeroCount;
}
int main() {
    int n;
    cin >> n;
    vector<int> vec(n);
    for (int i = 0; i < n; i++) cin >> vec[i];
    int result = 0;
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            if (countOnes(vec[i] * vec[j]) == 1)  result++;
        }
    }
    cout << result << endl;
}
```