Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.

当height[left] <= h时，只有left++才有可能提高面积！

class Solution {
public:
  int maxArea(vector<int>& height) {
    int left = 0, right = height.size()-1;
    int maxArea = 0;
    while (left < right){
      int h = min(height[left], height[right]);
      maxArea = max(maxArea, (right - left)*h);
      while (height[left] <= h && left < right)//<=h
        left++;
      while (height[right] <= h && left < right)
        right--;
    }
    return maxArea;
  }
};