Count Numbers with Unique Digits - Medium - NL
Published:
Question
- https://leetcode.com/problems/count-numbers-with-unique-digits/
Given an integer n, return the count of all numbers with unique digits, x, where 0 <= x < 10n.
Approach
- Count
Solution
class Solution {
public:
int countNumbersWithUniqueDigits(int n) {
if(n==0) {
return 1;
}
int ans = 10;
for(int i=2;i<=n;i++) {
int temp = 0;
temp = 9*9;
int y = 8;
for(int j=3;j<=i;j++) {
temp = temp*y;
y--;
}
ans += temp;
}
return ans;
}
};