Leetcode 2343 Query Kth Smallest Trimmed Number Solution in c++ | Hindi Coding Community

 

You are given a 0-indexed array of strings nums, where each string is of equal length and consists of only digits.

You are also given a 0-indexed 2D integer array queries where queries[i] = [ki, trimi]. For each queries[i], you need to:

• Trim each number in nums to its rightmost trimi digits.
• Determine the index of the kith smallest trimmed number in nums. If two trimmed numbers are equal, the number with the lower index is considered to be smaller.
• Reset each number in nums to its original length.

Return an array answer of the same length as queries, where answer[i] is the answer to the ith query.

Note:

• To trim to the rightmost x digits means to keep removing the leftmost digit, until only x digits remain.
• Strings in nums may contain leading zeros.

 

Example 1:

Input: nums = ["102","473","251","814"], queries = [[1,1],[2,3],[4,2],[1,2]]
Output: [2,2,1,0]
Explanation:
1. After trimming to the last digit, nums = ["2","3","1","4"]. The smallest number is 1 at index 2.
2. Trimmed to the last 3 digits, nums is unchanged. The 2nd smallest number is 251 at index 2.
3. Trimmed to the last 2 digits, nums = ["02","73","51","14"]. The 4th smallest number is 73.
4. Trimmed to the last 2 digits, the smallest number is 2 at index 0.
   Note that the trimmed number "02" is evaluated as 2.

Example 2:

Input: nums = ["24","37","96","04"], queries = [[2,1],[2,2]]
Output: [3,0]
Explanation:
1. Trimmed to the last digit, nums = ["4","7","6","4"]. The 2nd smallest number is 4 at index 3.
   There are two occurrences of 4, but the one at index 0 is considered smaller than the one at index 3.
2. Trimmed to the last 2 digits, nums is unchanged. The 2nd smallest number is 24.

 

Constraints:

• 1 <= nums.length <= 100
• 1 <= nums[i].length <= 100
• nums[i] consists of only digits.
• All nums[i].length are equal.
• 1 <= queries.length <= 100
• queries[i].length == 2
• 1 <= ki <= nums.length
• 1 <= trimi <= nums[i].length

 

Follow up: Could you use the Radix Sort Algorithm to solve this problem? What will be the complexity of that solution?

C++ Code :

class Solution {

public:

vector<int> smallestTrimmedNumbers(vector<string>& nums, vector<vector<int>>& queries) {

vector<vector<pair<string,int>>> table(nums[0].size() + 1, vector<pair<string,int>>(nums.size() ));

vector<int> ans(queries.size());

for(int i = 0; i != nums.size(); i++)

for(int j = nums[i].size() - 1, k = 1; j >=0; j--, k++)

table[k][i] = {nums[i].substr(j, k), i};

for(int i = 1; i != nums[0].size() + 1; i++)

sort(table[i].begin(), table[i].end(), [](pair<string,int> &a, pair<string,int> &b)

{return a.first == b.first ? a.second < b.second : a.first < b.first;});

for(int i = 0; i != queries.size(); i++)

ans[i] = table[queries[i][1]][queries[i][0]-1].second;

return ans;

}

};