1 題目要求：

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.

Note: You may not slant the container and n is at least 2.

Example:

Input: [1,8,6,2,5,4,8,3,7]
Output: 49

2 解決方法:

列舉法，挨個計算水量更新最大值。由大到小比情況較為複雜，由小至大比較時，僅當新的邊長比舊的邊長大才有可能獲得更大水量，作為條件簡化。

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

時間複雜度O(n)

空間複雜度O(1)