LeetCode之53. Maximum Subarray

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,    ----  动态规划

try coding another solution using the divide and conquer approach, which is more subtle.  ---- 分治法 ？？？

public int maxSubArray(int[] nums) {
    int[] dp = new int[nums.length];
	dp[0] = nums[0];
	int maxSum = nums[0]; 
     // 这里不能是Intger.MIN_VALUE，否则输入{1}，maxSum=-2147483648
	
	for(int i=1;i<dp.length;i++) {
		if(dp[i-1] <= 0) {
			dp[i] = nums[i];
		}else {
			dp[i] = dp[i-1] + nums[i];
		}
		
		if(dp[i] > maxSum) {
			maxSum = dp[i];
		}
	}
	
	return maxSum;
}

             1） for循环从i等于1开始， 那么我们就应该想到数组只有1个元素的时候，i只能等于0，根本没有机会进入这个for循环