leetcode

0 class Solution {

1 public:

2 int countNicePairs(const vector<int> &nums) const {

3 static const int MOD = 1E9 + 7;

4 unordered_map<int, int> count;

5 int res = 0;

6 for (const int n : nums) {

7 a int rev = 0, tmp = n;

8 do {

9 rev = (rev * 10) + tmp % 10;

10 } while ((tmp /= 10) > 0);

11 const int crnt = n - rev;

12 res = (res + count[crnt]++) % MOD;

13 }

14

15 return res;

16 }

17 };