【題解】AtCoder ABC160C – Traveling Salesman around Lake

#include <bits/stdc++.h>
using namespace std;

int l, n, a[200005], mx;

int main(){
    cin >> l >> n;
    cin >> a[0];
    for (int i = 1; i < n; i++){
        cin >> a[i];
        mx = max(mx, a[i]-a[i-1]);
    }
    mx = max(mx, l-a[n-1]+a[0]);
    cout << l-mx << "\n";
}