题目：
每次向最低的地方灌水，和下面这个三维的思想类似，也可以说是简化版本。
参考：
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| #include <vector>
#include <algorithm>
using std::vector;
class Solution {
public:
int trap(vector<int> &height)
{
int n = height.size();
int left_boundary = 0, right_boundary = n - 1;
int lower;
int rain = 0;
while (left_boundary < right_boundary) {
lower = std::min(height[left_boundary],
height[right_boundary]);
if (height[left_boundary] < height[right_boundary]) {
if (height[left_boundary + 1] <
height[left_boundary]) {
rain += height[left_boundary] -
height[left_boundary + 1];
height[left_boundary + 1] =
height[left_boundary];
}
left_boundary++;
} else {
if (height[right_boundary - 1] <
height[right_boundary]) {
rain += height[right_boundary] -
height[right_boundary - 1];
height[right_boundary - 1] =
height[right_boundary];
}
right_boundary--;
}
}
return rain;
}
};
|
hot100 rewrite
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| #include <vector>
using std::vector;
class Solution {
public:
int trap(vector<int> &height)
{
int n = height.size(), i = 0, j = n - 1;
int water = 0;
while (i < j && height[i] == 0) {
i++;
}
while (j > i && height[j] == 0) {
j--;
}
int tmp;
while (i < j) {
if (height[i] <= height[j]) {
tmp = i;
i++;
while (i < j && height[i] < height[tmp]) {
water += height[tmp] - height[i];
i++;
}
} else {
tmp = j;
j--;
while (i < j && height[j] < height[tmp]) {
water += height[tmp] - height[j];
j--;
}
}
}
return water;
}
};
|
