Class Solution

LeetCode_problems/Compare Version Number/solution2.cpp:23–74

AUTHOR: github.com/Sanjay235 LOGIC: ================================================================================================ 1. For every level `i` we get the corresponding number for both version strings by iterating untill a '.' dot delimiter is encountered. 2. Now we check if number for either version strings is greater than other and return accordingly. 3. Reset the numbers of l

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*/
class Solution {
public:
    int compareVersion(string version1, string version2) {
        
	// Get the length of each version strings.
        int n1 = version1.length(), n2 = version2.length();
		
	// Maintain variables for corresponding level number in each version string.
        int num1 = 0, num2 = 0;
        
	// Pointers for iterating two version strings.
        int i = 0, j = 0;
        
	// Continue iterating till each of the version strings are traversed completely.
        while(i < n1 || j < n2){
            
	    // Get the number for current level `i` of version string - 1.
            while(i < n1 && version1[i] != '.'){
                num1 = num1 * 10 + version1[i]-'0';
                ++i;
            }
			
	    // Get the number for current level `i` of version string - 2.
            while(j < n2 && version2[j] != '.'){
                num2 = num2 * 10 + version2[j]-'0';
                ++j;
            }
			
	    // If at anytime number for level `i` of version1 is greater than
	    // number for level `i` of version2, 
	    // then we can safely return `1` version1 is greater than version 2.
            if(num1 > num2) 
                return 1;
            
	    // If at anytime number for level `i` of version1 is less than
	    // number for level `i` of version2, 
	    // then we can safely return `-1` i.e version1 is less than version 2.
            if(num1 < num2) 
                return -1;
			
            // Reset the numbers for next level `i+1`
            num1 = num2 = 0;
            
	    // Move ahead for next level number comparision.
            ++i, ++j;
        }
		
	// We return 0 since the numbers at all levels of version1 and version2 are same.
	// i.e both version are same.
        return 0;
    }
};