(Leet Code JS)Container With Most Water

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 the line i is at (i, ai) and (i, 0). Find two lines, which, together with the x-axis forms a container, such that the container contains the most water.

Notice that you may not slant the container.

 

Example 1:

Input: height = [1,8,6,2,5,4,8,3,7] Output: 49 Explanation: The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.

Example 2:

Input: height = [1,1] Output: 1

Example 3:

Input: height = [4,3,2,1,4] Output: 16

Example 4:

Input: height = [1,2,1] Output: 2

 

Constraints:

• n == height.length
• 2 <= n <= 105
• 0 <= height[i] <= 104

투포인터 알고리즘.

front와 back으로 각각 height 배열의 0번째 인덱스와 마지막 인덱스를 넣어서 시작한다.

 

while문으로 최대 넓이 구하기.

height 배열 중 [front]와 [back]에 있는 값을 비교하여 더 작은 값을 변으로 정한다.

해당 변으로 직사각형의 넓이를 구한 후, 범위를 좁힌다.

또한, answer과 비교하여 더 큰 값을 갱신시키면 된다.

/**
 * @param {number[]} height
 * @return {number}
 */
const maxArea = function(height) {
    let front = 0;
    let back = height.length - 1;
    let answer = 0;
    
    while(front < back){
        let width = 0;
        
        if(height[front] < height[back]){
            width = height[front] * (back - front);
            front++;
        } else{
            width = height[back] * (back - front);
            back--;
        }
        
        answer = answer < width ? width : answer;
    }
    
    return answer;
};