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New Problem Solution -"1738. Find Kth Largest XOR Coordinate Value"
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haoel committed Mar 31, 2021
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Expand Up @@ -56,6 +56,7 @@ LeetCode
|1748|[Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/) | [C++](./algorithms/cpp/sumOfUniqueElements/SumOfUniqueElements.cpp)|Easy|
|1743|[Restore the Array From Adjacent Pairs](https://leetcode.com/problems/restore-the-array-from-adjacent-pairs/) | [C++](./algorithms/cpp/restoreTheArrayFromAdjacentPairs/RestoreTheArrayFromAdjacentPairs.cpp)|Medium|
|1742|[Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box/) | [C++](./algorithms/cpp/maximumNumberOfBallsInABox/MaximumNumberOfBallsInABox.cpp)|Easy|
|1738|[Find Kth Largest XOR Coordinate Value](https://leetcode.com/problems/find-kth-largest-xor-coordinate-value/) | [C++](./algorithms/cpp/findKthLargestXorCoordinateValue/FindKthLargestXorCoordinateValue.cpp)|Medium|
|1736|[Latest Time by Replacing Hidden Digits](https://leetcode.com/problems/latest-time-by-replacing-hidden-digits/) | [C++](./algorithms/cpp/latestTimeByReplacingHiddenDigits/LatestTimeByReplacingHiddenDigits.cpp)|Easy|
|1734|[Decode XORed Permutation](https://leetcode.com/problems/decode-xored-permutation/) | [C++](./algorithms/cpp/decodeXORedPermutation/DecodeXoredPermutation.cpp)|Medium|
|1733|[Minimum Number of People to Teach](https://leetcode.com/problems/minimum-number-of-people-to-teach/) | [C++](./algorithms/cpp/minimumNumberOfPeopleToTeach/MinimumNumberOfPeopleToTeach.cpp)|Medium|
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// Source : https://leetcode.com/problems/find-kth-largest-xor-coordinate-value/
// Author : Hao Chen
// Date : 2021-03-31

/*****************************************************************************************************
*
* You are given a 2D matrix of size m x n, consisting of non-negative integers. You are also given an
* integer k.
*
* The value of coordinate (a, b) of the matrix is the XOR of all matrix[i][j] where 0 <= i <= a < m
* and 0 <= j <= b < n (0-indexed).
*
* Find the k^th largest value (1-indexed) of all the coordinates of matrix.
*
* Example 1:
*
* Input: matrix = [[5,2],[1,6]], k = 1
* Output: 7
* Explanation: The value of coordinate (0,1) is 5 XOR 2 = 7, which is the largest value.
*
* Example 2:
*
* Input: matrix = [[5,2],[1,6]], k = 2
* Output: 5
* Explanation: The value of coordinate (0,0) is 5 = 5, which is the 2nd largest value.
*
* Example 3:
*
* Input: matrix = [[5,2],[1,6]], k = 3
* Output: 4
* Explanation: The value of coordinate (1,0) is 5 XOR 1 = 4, which is the 3rd largest value.
*
* Example 4:
*
* Input: matrix = [[5,2],[1,6]], k = 4
* Output: 0
* Explanation: The value of coordinate (1,1) is 5 XOR 2 XOR 1 XOR 6 = 0, which is the 4th largest
* value.
*
* Constraints:
*
* m == matrix.length
* n == matrix[i].length
* 1 <= m, n <= 1000
* 0 <= matrix[i][j] <= 10^6
* 1 <= k <= m * n
******************************************************************************************************/

class Solution {
private:
void print(vector<vector<int>>& m) {
int row = m.size();
int col = m[0].size();
for (int i=0; i<row; i++) {
for(int j=0; j<col-1; j++) {
cout << setw(3) << m[i][j] << ",";
}
cout << setw(3) << m[i][col-1] << endl;
}
cout << endl;
}
public:
int kthLargestValue(vector<vector<int>>& matrix, int k) {
int row = matrix.size();
int col = matrix[0].size();
vector<vector<int>> xmatrix(row, vector<int>(col, 0));
priority_queue<int> minHeap;

xmatrix[0][0] = matrix[0][0];
minHeap.push(xmatrix[0][0]);

for (int i=1; i<row; i++) {
xmatrix[i][0] = xmatrix[i-1][0] ^ matrix[i][0];
minHeap.push(xmatrix[i][0]);
}
for (int i=1; i<col; i++) {
xmatrix[0][i] = xmatrix[0][i-1] ^ matrix[0][i];
minHeap.push(xmatrix[0][i]);
}

for (int i=1; i<row; i++) {
for(int j=1; j<col; j++) {
xmatrix[i][j] = matrix[i][j] ^
xmatrix[i-1][j] ^ xmatrix[i][j-1] ^ xmatrix[i-1][j-1];
minHeap.push(xmatrix[i][j]);
}
}
//print(matrix);
//print(xmatrix);
while( k-- > 1) {
minHeap.pop();
}

return minHeap.top();
}
};

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