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-rw-r--r--find_kth_large_xor_coord.c42
-rw-r--r--find_kth_large_xor_coord.py41
2 files changed, 83 insertions, 0 deletions
diff --git a/find_kth_large_xor_coord.c b/find_kth_large_xor_coord.c
new file mode 100644
index 0000000..2611be1
--- /dev/null
+++ b/find_kth_large_xor_coord.c
@@ -0,0 +1,42 @@
+// 1738. Find Kth Largest XOR Coordinate Value
+#include "leetcode.h"
+
+/*
+ * 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'.
+ */
+
+int cmp(const void *a, const void *b) { return *(int *)a > *(int *)b; }
+
+int kthLargestValue(int **matrix, int matrixSize, int *matrixColSize, int k) {
+ int map[matrixSize * (*matrixColSize)], idx = 0;
+ for (int i = 0; i < matrixSize; i++)
+ for (int j = 0; j < *matrixColSize; j++) {
+ if (j > 0)
+ matrix[i][j] ^= matrix[i][j - 1];
+ if (i > 0)
+ matrix[i][j] ^= matrix[i - 1][j];
+ if (i > 0 && j > 0)
+ matrix[i][j] ^= matrix[i - 1][j - 1];
+ map[idx++] = matrix[i][j];
+ }
+ qsort(map, idx, sizeof(int), cmp);
+ return map[idx - k];
+}
+
+int main() {
+ int matrix_input[2][2] = {{5, 2}, {1, 6}};
+ struct two_d_arr matrix;
+ two_d_arr_init(&matrix, ARRAY_SIZE(matrix_input), ARRAY_SIZE(matrix_input[0]),
+ matrix_input);
+ printf("%d\n", kthLargestValue(matrix.arr, matrix.row_size, matrix.col_size,
+ 1)); // expect: 7
+ printf("%d\n", kthLargestValue(matrix.arr, matrix.row_size, matrix.col_size,
+ 2)); // expect: 5
+ printf("%d\n", kthLargestValue(matrix.arr, matrix.row_size, matrix.col_size,
+ 3)); // expect: 4
+ two_d_arr_free(&matrix);
+}
diff --git a/find_kth_large_xor_coord.py b/find_kth_large_xor_coord.py
new file mode 100644
index 0000000..feb19a8
--- /dev/null
+++ b/find_kth_large_xor_coord.py
@@ -0,0 +1,41 @@
+# 1738. Find Kth Largest XOR Coordinate Value
+import heapq
+
+"""
+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'.
+"""
+
+
+class Solution(object):
+ def kthLargestValue(self, matrix, k):
+ """
+ :type matrix: List[List[int]]
+ :type k: int
+ :rtype: int
+ """
+ m, n = len(matrix), len(matrix[0])
+ pq = []
+ for i in range(m):
+ for j in range(n):
+ if i > 0:
+ matrix[i][j] ^= matrix[i - 1][j]
+ if j > 0:
+ matrix[i][j] ^= matrix[i][j - 1]
+ if i > 0 and j > 0:
+ matrix[i][j] ^= matrix[i - 1][j - 1]
+ if len(pq) < k:
+ heapq.heappush(pq, matrix[i][j])
+ else:
+ heapq.heappushpop(pq, matrix[i][j])
+ return pq[0]
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(obj.kthLargestValue(matrix=[[5, 2], [1, 6]], k=1))
+ print(obj.kthLargestValue(matrix=[[5, 2], [1, 6]], k=2))
+ print(obj.kthLargestValue(matrix=[[5, 2], [1, 6]], k=3))