Largest Sum Contiguous Subarray code example

Example 1: maximum subarray solution leetcode

def approach3(nums):
    ans = nums[0]
    subarr_sum = nums[0]

    for i in range(1, len(nums)):
        subarr_sum = max(nums[i], nums[i] + subarr_sum)
        ans = max(ans, subarr_sum)

    return ans

Example 2: kadane algorithm

public int kadane(int[] arr){
	int max_so_far = 0, curr_max = Integer.MIN_VALUE;
    for(int i: arr){
    	max_so_far += i;
        if(max_so_far<0) max_so_far = 0;
        if(max_so_far>curr_max) curr_max = max_so_far;
    }
    return curr_max;
}

Example 3: largest subarray of 0's and 1's

public class Solution {

    public int findMaxLength(int[] nums) {
        Map<Integer, Integer> map = new HashMap<>();
        map.put(0, -1);
        int maxlen = 0, count = 0;
        for (int i = 0; i < nums.length; i++) {
            count = count + (nums[i] == 1 ? 1 : -1);
            if (map.containsKey(count)) {
                maxlen = Math.max(maxlen, i - map.get(count));
            } else {
                map.put(count, i);
            }
        }
        return maxlen;
    }
}