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：这道题就是求最大矩形面积。当长度减少时，高度必须增加才能增大面积。使用两个指针——首指针和尾指针,取min(ai,aj)*(j-i).如果头指针指向的结点小于尾指针指向的结点，这头指针向前移动，否则尾指针向前移动，再继续求解矩形面积。感觉就像贪心算法，如果距离减小，必须通过增加高度来弥补。

class Solution {
public:
int maxArea(vector<int> &height) {
int nSize=height.size();
if(nSize==0)
return 0;
int Area=0;
int mostWater=0;
vector<int>::iterator iter1=height.begin();
vector<int>::iterator iter2=height.end()-1;
while(iter1<iter2)
{
Area=min(*iter1,*iter2)*(iter2-iter1);
if(mostWater<Area)
mostWater=Area;
if(*iter1<*iter2)
iter1++;
else
iter2--;
}
return mostWater;
}
};