leetcode 42. Trapping Rain Water (hard)

版权声明：by ruohua3kou https://blog.csdn.net/ruohua3kou/article/details/89059715

找出最高的柱子，分别计算其两边的柱子
对左边的每个点而言

其左边最大柱子的高度 - 其本身的高度 = 这一点能容纳的水量

右边同理

class Solution
{
  public:
	int trap(vector<int> &height)
	{
		int partionPeak = 0;
		int sumWater = 0;
		// 分界点
		for (int i = 0; i < height.size(); i++)
			if (height[i] > height[partionPeak])
				partionPeak = i;

		int leftPeak = 0;
		for (int i = 0; i < partionPeak; i++)
		{
			if (height[i] > leftPeak)
				leftPeak = height[i];
			else
				sumWater += leftPeak - height[i];
		}
		int rightPeak = 0;
		for (int i = height.size() - 1; i > partionPeak; i--)
		{
			if (height[i] > rightPeak)
				rightPeak = height[i];
			else
				sumWater += rightPeak - height[i];
		}
		return sumWater;
	}
};