LeetCode 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.

Note: You may not slant the container.

思路分析：这题考察双指针和贪心，左右两个指针，从两端開始，假设左边较矮，那么我们移动左边指针向右，去看是否能找到更高的左“墙”，假设找到，就计算面积更新下眼下的maxArea；假设右边较矮，那么我们移动右边指针向左，去看是否能找到更高的右“墙”，假设找到，就计算面积更新下眼下的maxArea，直到两个指针相遇，返回maxArea

AC Code

public class Solution {
    public int maxArea(int[] height) {
        int l, r, lh, rh, max, temp;
        l = 0;
        r = height.length - 1;
        lh = height[l];
        rh = height[r];
        max = 0;
        
        while(l < r){
            temp = Math.min(lh, rh) * (r - l);
            if(max < temp) {
                max = temp;
            }
            
            if(lh > rh){
                //move r
                while(l < r && height[r] <= rh){
                    r--;
                } 
                if(l < r){
                    rh = height[r];
                }
            } else {
                //move l
                while(l < r && height[l] <= lh){
                    l++;
                } 
                if(l < r){
                    lh = height[l];
                }
            }
        }
        return max;
    }
}