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public class SearchinSortedMatrix {

public static int binarySearch(int arr[], int key) {

int low = 0;

int high = arr.length - 1;

while (low <= high) {

int mid = low + (high - low) / 2;

if (arr[mid] == key) {

return mid;

} else if (arr[mid] > key) {

high = mid - 1;

} else {

low = mid + 1;

}

}

return -1;

}

public static String binaryMatrixSearch(int mat[][], int key) {

int index = 0;

for (int i = 0; i < mat.length; i++) {

index = binarySearch(mat[i], key);

if (index != -1) {

return "key found at index (" + i + "," + index + ")";

}

}

return "Key not found";

// Time Complexity:O(nlogn)

}

public static String Optimisedsearch(int mat[][], int key) {

int row = 0, col = mat[0].length - 1;

while (row < mat.length && col >= 0) {

if (mat[row][col] == key) {

return "key found at index (" + row + "," + col + ")";

} else if (key < mat[row][col]) {

col--;

} else {

row++;

}

}

return "Key not found";

}

public static void main(String[] args) {

int matrix[][] = { { 1, 2, 3, 4, 5 },

{ 6, 7, 8, 9, 10 },

{ 18, 12, 18, 14, 15 },

{ 16, 17, 18, 19, 20 },

{ 21, 22, 23, 24, 25 } };

int key = 18;

System.out.println(binaryMatrixSearch(matrix, key));

System.out.println(Optimisedsearch(matrix, key));

}

}