题解 | #小美走公路#

加一倍，变成一个环就行了，注意处理细节问题。

#include <iostream>
#include <queue>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <iomanip>
#include <stack>
#include <numeric>
#include <ctime>
#include <string>
#include <bitset>
#include <unordered_map>
#include <unordered_set>

using namespace std;
using ll = long long;
const ll N = 1e5 + 5, mod = 1e9 + 7, inf = 0x3f3f3f3f;

int n, m;
ll a[N << 1];

void solve() {
    cin >> n;

    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        a[n + i] = a[i];
    }

    for (int i = 1; i <= 2 * n; i++) {
        a[i] += a[i - 1];
    }
    int s, t;
    cin >> s >> t;
    if (s > t)swap(s, t);

    cout << min(a[t-1] - a[s-1], a[s + n - 1] - a[t - 1]);
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int t = 1;
    //cin >> t;

    while (t--) {

        solve();

    }

    return 0;
}