Find the contiguous subarray within an array (containing at least one number) which has the largest sum.
For example, given the array [-2,1,-3,4,-1,2,1,-5,4],
the contiguous subarray [4,-1,2,1] has the largest sum = 6.
此题和Maximum product subarray很像，只不过比那个简单一点，也是用的动态规划做法做的，首先思考最优子结构性质，前面的最优解+当前数组值和当前数组值进行比较，取较大的值，直到求到全局解。重叠子问题也存在，将前面的最优解的值存放在了res里面，代码如下：
public class Solution {
public int maxSubArray(int[] nums) {
if(nums.length==0) return 0;
int res = nums[0];
int cur = nums[0];
for(int i=1;i<nums.length;i++){
cur = Math.max(cur+nums[i],nums[i]);
res = Math.max(cur,res);
}
return res;
}
}