2342. Max Sum of a Pair With Equal Sum of Digits
## 思路
用hash table紀錄digitSum的最大值
table有相同的digitSum就計算兩數和
## Code
```cpp
class Solution {
public:
int maximumSum(vector<int>& nums) {
unordered_map<int, int> table;
int res = -1;
for (int& num: nums) {
int digitSum = getDigitSum(num);
if (table.contains(digitSum)) {
res = max(res, table[digitSum] + num);
table[digitSum] = max(table[digitSum], num);
} else {
table[digitSum] = num;
}
}
return res;
}
private:
int getDigitSum(int num) {
int res = 0;
while (num > 0) {
res += num % 10;
num /= 10;
}
return res;
}
};
```