Me:
I have a problem written in Chinese, you must understand it and work out a proper solution in C++. Note that the problem consisted of 5 sections, meaning of every parts are explained as following:
Problem Description: as it being stated, the description of the problem itself.
Input: stating the constraint of the data set that will be passed to your solution.
Output: stating the requirements that the results from your solution must satisfy.
Sample Input: you're not conscious of all the data set, so it's just a sample show you what kind of data will be passed to your solution.
Sample Output: that's the expected output your solution should work out for the Sample Input.
Do you understand?
ChatGPT:
Yes, I understand. Please provide me with the problem description and I will try my best to provide you with a solution in C++.
Me:
Here's the problem:
Problem Description
Zyj发明了一台3D打印机,但他的技术不过关,这台打印机的喷嘴频繁喷喷停停的话是会坏掉哒,所以Zyj为了尽量保证喷嘴能够尽量连续地喷出物料,设计了一个很蠢的方法:
一个打印物件可以大致分为n个部分,每个部分要求达到高度hi。每次可以选择从第L部分到第R部分(L≤R)喷上一层物料,可以增加高度1。请你帮助他算一算,对于给定的打印物件,至少需要喷涂多少次物料。
Input
第一行是整数T,代表测试数据的组数(T ≤ 10)。
每组数据中,第一行是整数n(1≤n≤105),表示打印物件有几个部分。
接下来第二行包含n个用空格间隔的整数,每个整数hi(0≤hi≤105)代表该部分需求的高度。
Output
对于每组数据,输出需要喷涂的最少次数,每个结果占据一行。
Sample Input
3
5
1 2 3 4 5
7
3 2 1 4 1 2 3
10
3 1 4 1 5 9 2 6 5 3
Sample Output
5
8
18
ChatGPT:
Here is a solution in C++:
```
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int MAXN = 100005;
int n;
int h[MAXN], s[MAXN];
int main() {
int t;
cin >> t;
while (t--) {
cin >> n;
memset(s, 0, sizeof(s));
for (int i = 1; i <= n; i++) {
cin >> h[i];
}
for (int i = 1; i <= n; i++) {
s[i] = s[i-1] + h[i];
}
int ans = 0, pre = 0;
for (int i = 1; i <= n; i++) {
ans += (s[i] - s[pre] >= i - pre);
if (s[i] - s[pre] < i - pre) pre = i - 1;
}
cout << ans << endl;
}
return 0;
}
```
Explanation:
The problem requires us to find the minimum number of times that the printer needs to spray material on a 3D object. We can approach this problem by using the prefix sum technique.
Firstly, we calculate the prefix sum of the height of each section of the object, denoted by `s`. Then, we iterate through each section of the object from left to right, and maintain a variable `pre` that represents the last section that has been sprayed with material. If the difference between `s[i]` and `s[pre]` is greater than or equal to the distance between the current section and the last sprayed section, we can spray material on the current section, and update `pre` to `i-1`.
Finally, the answer is the number of sections that have been sprayed with material.
The time complexity of this solution is O(n), where n is the number of sections in the object.