Maximum Subarray | Leetcode

Given an integer array nums
, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Maximum Subarray is the contiguous array with maximum sum.
A subarray is a contiguous part of an array.
Example 1:
Input: nums = [-2,1,-3,4,-1,2,1,-5,4] Output: 6 Explanation: [4,-1,2,1] has the largest sum = 6.
Example 2:
Input: nums = [1] Output: 1
Example 3:
Input: nums = [5,4,-1,7,8] Output: 23
Example 4:
Input: nums = [-2,-4,-1,-5,-7] Output: -1
Constraints:
1 <= nums.length <= 105
-104 <= nums[i] <= 104
Solution
[code lang=”java”]
class Solution {
public int maxSubArray(int[] nums)
{
/*If array is empty return 0*/
if(nums!= null && nums.length == 0)
{
return 0;
}
int max=nums[0],sum=0;
for(int i =0; i<nums.length; i++)
{
/* Case 1 : If sum is a negative number Say -3 and nums[i] = -2 . Assign smallest negative -2 as
Sum.
* Case 2: If sum is negative and nums[i] =1. Assign Sum = 1
*/
if(sum<nums[i] && sum<0)
{
sum = nums[i];
}
else
{
sum+= nums[i];
}
if(sum>max)
{
max = sum;
}
}
return max;
}
}
[/code]
Time Complexity
Loop is running for n times so O(n) where n is the length of the array
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