#383 Container With Most Water

题目描述：

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.


 Notice

You may not slant the container.

Have you met this question in a real interview? 

Yes

Example

Given 

[1,3,2]

, the max
area of the container is 

2

.

题目思路：

根据木桶理论，最大的area是由短板决定的。这题可以用两个指针，一个初始指向左端，一个初始指向右端，得到一个当前的area。如何找可能更大的area？如果移动更高的那个指针，由于width变小，得到的area只能更小；所以我们只需要移动height更低的那个指针，找到新位置的area，然后与之前的area做max即可。

Mycode（AC = 38ms）：

class Solution {
public:
/**
* @param heights: a vector of integers
* @return: an integer
*/
int maxArea(vector<int> &heights) {
// write your code here
int l = 0, r = heights.size() - 1;
int area = 0;

while (l < r) {
// find the area of current height and width
int tmp = min(heights[l], heights[r]) * (r - l);

// for shorter height, move the index forward
if (heights[l] <= heights[r]) {
l++;
}
else {
r--;
}

// get max area
area = max(tmp, area);
}

return area;
}
};