Question 54 of 75 - LeetCode Weekly Challenge

LeetCode Challenge #2300. Successful Pairs of Spells and Potions

You are given two positive integer arrays spells and potions, of length n and m respectively, where spells[i] represents the strength of the ith spell and potions[j] represents the strength of the jth potion.

You are also given an integer success. A spell and potion pair is considered successful if the product of their strengths is at least success.

Return an integer array pairs of length n where pairs[i] is the number of potions that will form a successful pair with the ith spell.

 

Example 1:

Input: spells = [5,1,3], potions = [1,2,3,4,5], success = 7
Output: [4,0,3]
Explanation:
- 0th spell: 5 * [1,2,3,4,5] = [5,10,15,20,25]. 4 pairs are successful.
- 1st spell: 1 * [1,2,3,4,5] = [1,2,3,4,5]. 0 pairs are successful.
- 2nd spell: 3 * [1,2,3,4,5] = [3,6,9,12,15]. 3 pairs are successful.
Thus, [4,0,3] is returned.

Example 2:

Input: spells = [3,1,2], potions = [8,5,8], success = 16
Output: [2,0,2]
Explanation:
- 0th spell: 3 * [8,5,8] = [24,15,24]. 2 pairs are successful.
- 1st spell: 1 * [8,5,8] = [8,5,8]. 0 pairs are successful. 
- 2nd spell: 2 * [8,5,8] = [16,10,16]. 2 pairs are successful. 
Thus, [2,0,2] is returned.

 

Constraints:

  • n == spells.length
  • m == potions.length
  • 1 <= n, m <= 105
  • 1 <= spells[i], potions[i] <= 105
  • 1 <= success <= 1010
Video Solution
C++ Solution
				
					class Solution {
public:
    int potionCount(vector<int> &potions, long long spell, long long success)
    {
        long long start=0;
        long long end=potions.size()-1;
        long long mid=start+(end-start)/2;
        long long ans=-1;

        while(start<=end)
        {
            mid=start+(end-start)/2;
            if(spell*potions[mid]>=success)
            {
                ans=mid;
                end=mid-1;
            }
            else if(spell*potions[mid]<success)start=mid+1;
        }

        if(ans==-1)return 0;
        
        return potions.size()-ans;

    }
    vector<int> successfulPairs(vector<int>& spells, vector<int>& potions, long long success) {
        vector<int> pairs;
        sort(potions.begin(),potions.end());

        for(auto i:spells)
        {
            int ans=potionCount(potions,i,success);
            pairs.push_back(ans);
        }
        return pairs;
    }
};
				
			

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