2 pointer
class Solution {
public int maxArea(int[] nums) {
if(nums == null || nums.length < 2) return 0;
int low = 0, high = nums.length - 1;
int res = Integer.MIN_VALUE;
while(low < high) {
int left = nums[low], right = nums[high];
if(left < right) {
res = Math.max(res, (high - low) * left);
low++;
} else {
res = Math.max(res, (high - low) * right);
high--;
}
}
return res;
}
}