1295. Find Numbers with Even Number of Digits

發表於 | 分類於

problem

solution

option 1

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class Solution {
public:
    int digits(int n){
        int  d= 0 ;
        while(n){
            d++;
            n/=10;
        }
        return d;
    }
    int findNumbers(vector<int>& nums) {
        int count;
        for(int n:nums) count+=(digits(n)%2==0?1:0);
        return count;
    }
};

option 2 - math

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class Solution {
public:
    int findNumbers(vector<int>& nums) {
        int count = 0;
        for(int n:nums){
            int temp = floor(log10(n))+1;
            count+=(temp%2==0?1:0);
        }
        return count;
    }
};

analysis

  • option 1
    • time complexity O(nlogn)
    • space complexity O(1)
  • option 2
    • time complexity O(n)
    • space complexity O(1)