题目:
题解:
int countNumbersWithUniqueDigits(int n) {if (n == 0) {return 1;}if (n == 1) {return 10;}int ans = 10, cur = 9;for (int i = 0; i < n - 1; ++i) {cur *= 9 - i;ans += cur;}return ans;
}
题目:
题解:
int countNumbersWithUniqueDigits(int n) {if (n == 0) {return 1;}if (n == 1) {return 10;}int ans = 10, cur = 9;for (int i = 0; i < n - 1; ++i) {cur *= 9 - i;ans += cur;}return ans;
}