Air conditioning (daily question 50 in spring)

Farmer John Of $N$ Cows are very picky about the room temperature in their barn .

Some cows prefer a lower temperature , Some cows prefer higher temperatures .

Farmer John The cowshed contains a row of $N$ Cattle pen , The number is $1\dots N$, There is a cow in each corral .

The first $i$ The cow wants the temperature in her barn to be $p_i$, And now the temperature in her bullpen is $t_i$.

To make sure every cow feels comfortable ,Farmer John A new air conditioning system has been installed .

The way the system is controlled is very interesting , He can send commands to the system , Tell it to raise or lower the temperature in a continuous set of corrals $1$ A unit of —— for example 「 Corral the cattle $5\dots 8$ The temperature of $1$ A unit of 」.

A continuous set of bullpen can contain only one bullpen .

Please help Farmer John Find the minimum number of commands he needs to send to the new air conditioning system , Make each cow's barn at the ideal temperature of the cow in it .

Input format
The first line of input contains $N$.

The next line contains $N$ Nonnegative integers $p_1\dots p_N$, Separate... With spaces .

The last line contains $N$ Nonnegative integers $t_1\dots t_N$.

Output format
Output an integer , by Farmer John The minimum number of instructions to use .

Data range
$1\le N\le 10^5$,
$0\le p_i,t_i\le 10000$

sample input ：

5
1 5 3 3 4
1 2 2 2 1

sample output ：

5

Sample explanation
A set of optimal Farmer John The instructions you can use are as follows ：

 initial temperature      ：1 2 2 2 1
 Raise the cowshed  2..5：1 3 3 3 2
 Raise the cowshed  2..5：1 4 4 4 3
 Raise the cowshed  2..5：1 5 5 5 4
 Lower the cowshed  3..4：1 5 4 4 4
 Lower the cowshed  3..4：1 5 3 3 4

---

Ideas ：

It is equivalent to changing the second array into the first array （ Only one continuous interval can be tested at a time $+1$ perhaps $-1$ operation ）
You can subtract the corresponding position number of the first array from the second array （ That is, their difference ）
The corresponding meaning of the title is to change all the elements of the difference array into $0$
Then find the difference array of the difference array （ The original array is all changed to $0$ The corresponding difference becomes $0$）
An interval operation on the original array is equivalent to changing two array elements of the difference group （ If the operation is $[l,r]$ Section +1, It's equivalent to $Badbranch[l]+1,Badbranch[r+1]-1$ ）, The difference array becomes $0$, You need to do $max$( Sum of positive numbers , Sum of absolute values of negative numbers ) operations .
If $su{m}_a>su{m}_b$ , Before $su{m}_b$ The second operation is to subtract a positive number $1$, Add... To a negative number $1$, The rest $su{m}_a-su{m}_b$ The second operation is performed on the remaining positive or negative numbers $-1/+1$ operation , And yes $n+1$ Position to proceed $+1/-1$ operation $(n+1)$ The element of position has no effect on the original array .

#include<iostream>

using namespace std;

const int N = 100010;

int n;
int a[N];

int main(){
    
    
    cin >> n;
    for(int i = 0; i < n; i++ ) scanf("%d", &a[i]);
    int x;
    for(int i = 0; i < n; i++) scanf("%d", &x), a[i] -= x;
    
    for(int i = n - 1; i > 0; i--) a[i] -= a[i-1];
    
    int neg = 0, pos = 0;
    for(int i = 0; i < n; i++)
        if(a[i] > 0) pos += a[i];
        else neg -= a[i];
    
    printf("%d\n", max(neg, pos));
    
    return 0;
}