Trees in a Row

题意翻译

## 题意 有$n$个正整数，可以对一个数进行修改(修改后也是正整数)，要求修改之后满足$a_i+k=a_{i+1}$,求最少的修改次数以及具体的修改方案 ## 输入格式 第一行:$n$和$k$ 第二行:$n$个数,表示初始的$a_i$ ## 输出格式 若不用修改,只要输出0 若需要修改; - 第一行:最小的修改次数 - 接下来的若干行,对于**被修改的**$a_i$,其修改后值为$b_i$,若$b_i>a_i$,输出:"+ i ($b_i-a_i$)";若$a_i>b_i$,输出:"- i $(a_i-b_i)$"

题目描述

The Queen of England has $ n $ trees growing in a row in her garden. At that, the $ i $ -th $ (1<=i<=n) $ tree from the left has height $ a_{i} $ meters. Today the Queen decided to update the scenery of her garden. She wants the trees' heights to meet the condition: for all $ i $ $ (1<=i&lt;n) $ , $ a_{i+1}-a_{i}=k $ , where $ k $ is the number the Queen chose. Unfortunately, the royal gardener is not a machine and he cannot fulfill the desire of the Queen instantly! In one minute, the gardener can either decrease the height of a tree to any positive integer height or increase the height of a tree to any positive integer height. How should the royal gardener act to fulfill a whim of Her Majesty in the minimum number of minutes?

输入输出格式

输入格式

The first line contains two space-separated integers: $ n $ , $ k $ ( $ 1<=n,k<=1000) $ . The second line contains $ n $ space-separated integers $ a_{1},a_{2},...,a_{n} $ ( $ 1<=a_{i}<=1000 $ ) — the heights of the trees in the row.

输出格式

In the first line print a single integer $ p $ — the minimum number of minutes the gardener needs. In the next $ p $ lines print the description of his actions. If the gardener needs to increase the height of the $ j $ -th ( $ 1<=j<=n $ ) tree from the left by $ x $ $ (x>=1) $ meters, then print in the corresponding line "+ j x". If the gardener needs to decrease the height of the $ j $ -th ( $ 1<=j<=n $ ) tree from the left by $ x $ $ (x>=1) $ meters, print on the corresponding line "- j x". If there are multiple ways to make a row of trees beautiful in the minimum number of actions, you are allowed to print any of them.

输入输出样例

输入样例 #1

4 1
1 2 1 5

输出样例 #1

2
+ 3 2
- 4 1

输入样例 #2

4 1
1 2 3 4

输出样例 #2

0