lintcode-medium-Container with Most Water

Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate

(i, ai)

. nvertical 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.

Given

[1,3,2]

, the max area of the container is

2

.

思路：

用左右两个指针向中间移动，记录任一时刻的截面积，如果比之前的结果大，就更新结果

当左边高度大于右边事，如果移动左边，则接下来的结果不会大于现在的结果，所以要移动右边，反之亦然，结论是总是移动高度较小的边

public class Solution {
/**
* @param heights: an array of integers
* @return: an integer
*/
public int maxArea(int[] heights) {
// write your code here

if(heights == null || heights.length == 0)
return 0;

int left = 0;
int right = heights.length - 1;
int result = 0;

while(left < right){
int area = (right - left) * Math.min(heights[left], heights[right]);
if(area > result)
result = area;

if(heights[left] > heights[right])
right--;
else
left++;

}

return result;
}
}