11. Container With Most Water
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.
时间复杂度:O(n)
空间复杂度:O(1)
一开始可能会这样做:将每一个区间都遍历一次,再从中选出最大值。但其实不需要,面积取决于长度和最低板的高度,每次改变左右两块板中最小的一个。
class Solution {
public int maxArea(int[] height) {
int length = height.length;
if(length < 2)
return 0;
if(length == 2){
return Math.min(height[0],height[1]) * 1;
}
int max = Integer.MIN_VALUE;
int start = 0;
int end = length - 1;
while(start < end){
int minHeight = Math.min(height[start],height[end]);
max = Math.max(max,minHeight * (end - start));
if(height[start] > height[end]){
end--;
}else if(height[start] < height[end]){
start++;
}else{
start++;
end--;
}
}
return max;
}
}