<p>Given an integer array <code>nums</code>, find the <span data-keyword="subarray-nonempty">subarray</span> with the largest sum, and return <em>its sum</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [-2,1,-3,4,-1,2,1,-5,4]
<strong>Output:</strong> 6
<strong>Explanation:</strong> The subarray [4,-1,2,1] has the largest sum 6.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [1]
<strong>Output:</strong> 1
<strong>Explanation:</strong> The subarray [1] has the largest sum 1.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [5,4,-1,7,8]
<strong>Output:</strong> 23
<strong>Explanation:</strong> The subarray [5,4,-1,7,8] has the largest sum 23.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>4</sup> &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
</ul>

<p>&nbsp;</p>
<p><strong>Follow up:</strong> If you have figured out the <code>O(n)</code> solution, try coding another solution using the <strong>divide and conquer</strong> approach, which is more subtle.</p>

import sys

class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        # sub_sum=0
        # max_sum=-sys.maxsize - 1
        
        # n=len(nums)
        # for i in range(n):
        #     max_sum=(-sys.maxsize - 1)
        #     sum=(-sys.maxsize - 1)
        #     for j in range(i,n)):

        #kandane algorithm
        ## intution - dont consider the subarray if sum<0 , and keep a seperate tracker for max
        #  and update it if the sum > max

        ## to keep track of maximum subarray we will use another pointer, when ever sum becomes <0 we move the integer
        
        sub_sum=0
        max_sum=-sys.maxsize-1
        
        for i in range(len(nums)):
            if sub_sum==0:
                start=i
            
                
            sub_sum+=nums[i]
            
            if(sub_sum>max_sum):
                max_sum=sub_sum
                ans_start=start
                ans_end=i
            if sub_sum<0:
                sub_sum=0
        print(nums[ans_start:ans_end])
        return max_sum

                
                
30500