B. Xenia and Ringroad1000 / 水题 模拟

Posted 2021-10-02 幽殇默

https://codeforces.com/problemset/problem/339/B

#include<bits/stdc++.h>
using namespace std;
int n,m,startx=1;
long long int sum;
int main(void)
{
	cin>>n>>m;
	for(int i=0;i<m;i++)
	{
		int s; cin>>s;
		if(s>=startx) sum+=s-startx;
		else sum+=n-startx+s;
		startx=s;
	}
	cout<<sum<<endl;
	return 0;
}