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Binary-Search-1 completed #2165

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30 changes: 30 additions & 0 deletions 2DMatrixSearch.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
/* Solved this using imaginary flattened 1D array
* Time complexity is O(LogN)

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Complexity should be in terms of m and n since it as a matrix

*/

class Solution {
public boolean searchMatrix(int[][] matrix, int target) {

int m = matrix.length;
if (m == 0) return false;
int n = matrix[0].length;
int low = 0;
int high = m * n - 1;
int mid;
int elemnt;
while(low <= high){
mid = (low + high) / 2;
elemnt = matrix[mid/n][mid%n];

if(target == elemnt) return true;
else{
if(target < elemnt) high = mid - 1;
else low = mid + 1;
}

}


return false;
}
}
30 changes: 30 additions & 0 deletions InfiniteSortedArray.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
/**
* Solving using binary search, first trying to find the high point in the array
* Then runing Binary search in the remaining portion.
* Time complexity of O(LogN + LogM)
*/

class Solution {
public int search(ArrayReader reader, int target) {
int low = 0;
int high = 1;
if(reader.get(low) == target) return low;
while(reader.get(high) <= target){
low = high;
high *= 2;
}

while(low <= high){
int mid = (low + high) / 2;
if(reader.get(mid) == target) return mid;
if(reader.get(mid) > target){
high = mid - 1;
}
else{
low = mid + 1;
}
}

return -1;
}
}
35 changes: 35 additions & 0 deletions RotatedSortedArray.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
/* SOlved using Binary search
* Trying to find the sorted portion of tha array and then checking whether target
* falls into that portion, otherwise removing the entire sorted portion
* Time complexity will be O(LogN)
*/

class Solution {
public int search(int[] nums, int target) {
int low = 0, high = nums.length - 1;

while (low <= high) {
int mid = (low + high) / 2;

if (nums[mid] == target) {
return mid;
}

if (nums[low] <= nums[mid]) {
if (nums[low] <= target && target < nums[mid]) {
high = mid - 1;
} else {
low = mid + 1;
}
} else {
if (nums[mid] < target && target <= nums[high]) {
low = mid + 1;
} else {
high = mid - 1;
}
}
}

return -1;
}
}