Check if Number Has Equal Digit Count and Digit Value

You are given a 0-indexed string num of length n consisting of digits.

Return true if for every index i in the range 0 <= i < n, the digit i occurs num[i] times in num, otherwise return false.

 

Example 1:

Input: num = "1210"
Output: true
Explanation:
num[0] = '1'. The digit 0 occurs once in num.
num[1] = '2'. The digit 1 occurs twice in num.
num[2] = '1'. The digit 2 occurs once in num.
num[3] = '0'. The digit 3 occurs zero times in num.
The condition holds true for every index in "1210", so return true.
Example 2:

Input: num = "030"
Output: false
Explanation:
num[0] = '0'. The digit 0 should occur zero times, but actually occurs twice in num.
num[1] = '3'. The digit 1 should occur three times, but actually occurs zero times in num.
num[2] = '0'. The digit 2 occurs zero times in num.
The indices 0 and 1 both violate the condition, so return false.
 

Constraints:

n == num.length
1 <= n <= 10
num consists of digits.


SOLUTION

class Solution {
public:
    
    int store[10];
    bool digitCount(string num) {
       // int n = num.size();
        
      //  vector<int> store(n,0);
        
        
        for(char c : num)
        {
            store[c-'0']++;
        }
        
        for(int i = 0; i < num.size(); i++)
        {
            if(num[i] - '0' != store[i])
                return false;
        }
        
        return true;
        
    }
};


Java HashMap Solution:


class Solution {
    public boolean digitCount(String num) {
          HashMap<Integer,Integer> map = new HashMap<>();
        for(int number = 0; number < num.length(); number++){
            int frequency = Character.getNumericValue(num.charAt(number));
            map.put(number,frequency);
        }

        for(int index = 0; index< num.length(); index++) {
            if (Character.getNumericValue(num.charAt(index)) < num.length()) {
                int frequency = map.get(Character.getNumericValue(num.charAt(index))) - 1;
                map.put(Character.getNumericValue(num.charAt(index)), frequency);
            }
        }
        for (int i = 0; i < num.length(); i++) {
            if(map.get(i) !=0){
                return false;
            }
        }

        return true;
    }
}