比对了很多题解也没发现错误，求助各位大佬

#include <cstdio>
#include <cmath>
using namespace std;
int a[100005];
int L, N, K;
bool check(int x) {
    int cnt = 0;
    for (int i = 2; i <= N; i++)
        if (a[i] - a[i-1] > x)
        {
            cnt += (a[i] - a[i-1]) / x;
            if (a[i] - a[i-1] % x == 0)
                cnt--;
        }
    return cnt <= K;
}
int main() {
    scanf("%d %d %d", &L, &N, &K);
    int l = 1, r = L, mid, ans;
    for (int i = 1; i <= N; i++)
        scanf("%d", a+i);
    while (l <= r)
    {
        mid  = l + (r - l) / 2;
        if (check(mid))
            ans = mid, r = mid - 1;
        else
            l = mid + 1;
    }
    printf("%d", ans);
    return 0;
}