Given an integer array
nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
Example:
Input: [-2,1,-3,4,-1,2,1,-5,4], Output: 6 Explanation: [4,-1,2,1] has the largest sum = 6.
Follow up:
If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.
Java Solution :
class Solution {
public int maxSubArray(int[] nums) {
int dp[] = new int[nums.length];
dp[0] = nums[0];
for(int i=1;i<nums.length;i++){
dp[i] = Math.max(dp[i-1] + nums[i],nums[i]);
}
int maxValue = dp[0];
for(int i = 1;i < nums.length;i++){
maxValue = Math.max(maxValue,dp[i]);
}
return maxValue;
}
}
Time Complexity : O(n)
Space Complexity: O(n) because we are using an array of size n.
Second Solution :
class Solution {
public int maxSubArray(int[] nums) {
int maxValue = nums[0];
for(int i=1;i<nums.length;i++){
nums[i] = Math.max(nums[i-1] + nums[i],nums[i]);
}
for(int i = 1;i < nums.length;i++){
maxValue = Math.max(maxValue,nums[i]);
}
return maxValue;
}
}
Time Complexity : O(n)
