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.

题意大概是：给一个数组height[n]，其中每一个元素height[i]=num,i代表它的横坐标，num代表纵坐标，要求由这个数组任意两个元素围成的面积最大的。 可以想象，如果最大由【i，j】对应构成，假设i<j,那么，i左边的所有元素高度都应当小于i 对应的高度，j右边所有元素高度都应该低于j对应的高度。所以可以从数组两边开始收缩，高度小的那边开始向中间收缩，直到找到一个高度比它高的才停止。

int maxArea(int* height, int heightSize) {
    int maxarea = -1,area,head=0,tail=heightSize-1,p;
    while(head<tail){
        area = (height[head]<height[tail]?height[head]:height[tail])*(tail-head);
        maxarea = maxarea>area?maxarea:area;
        if(height[head]<height[tail]){
            p = head;
            while(head<tail&&height[head]<=height[p]) head++;
            }
        else{
            p = tail;
            while(head<tail&&height[tail]<=height[p]) tail--;
        }
    }
    return maxarea;
}