A15030. Make it Increasing
编程题
普及/提高-
知识点
题目描述
You are given an array $a$ consisting of $n$ positive integers, and an array $b$ , with length $n$ . Initially $b_i=0$ for each $1 \leq i \leq n$ .
In one move you can choose an integer $i$ ( $1 \leq i \leq n$ ), and add $a_i$ to $b_i$ or subtract $a_i$ from $b_i$ . What is the minimum number of moves needed to make $b$ increasing (that is, every element is strictly greater than every element before it)?
In one move you can choose an integer $i$ ( $1 \leq i \leq n$ ), and add $a_i$ to $b_i$ or subtract $a_i$ from $b_i$ . What is the minimum number of moves needed to make $b$ increasing (that is, every element is strictly greater than every element before it)?
输入格式
The first line contains a single integer $n$ ( $2 \leq n \leq 5000$ ).
The second line contains $n$ integers, $a_1$ , $a_2$ , ..., $a_n$ ( $1 \leq a_i \leq 10^9$ ) — the elements of the array $a$ .
The second line contains $n$ integers, $a_1$ , $a_2$ , ..., $a_n$ ( $1 \leq a_i \leq 10^9$ ) — the elements of the array $a$ .
输出格式
Print a single integer, the minimum number of moves to make $b$ increasing.
输入输出样例
输入 #1
5 1 2 3 4 5
输出 #1
4
输入 #2
7 1 2 1 2 1 2 1
输出 #2
10
输入 #3
8 1 8 2 7 3 6 4 5
输出 #3
16
说明/提示
Example $1$ : you can subtract $a_1$ from $b_1$ , and add $a_3$ , $a_4$ , and $a_5$ to $b_3$ , $b_4$ , and $b_5$ respectively. The final array will be \[ $-1$ , $0$ , $3$ , $4$ , $5$ \] after $4$ moves.
Example $2$ : you can reach \[ $-3$ , $-2$ , $-1$ , $0$ , $1$ , $2$ , $3$ \] in $10$ moves.
Example $2$ : you can reach \[ $-3$ , $-2$ , $-1$ , $0$ , $1$ , $2$ , $3$ \] in $10$ moves.