AcWing 519.跳石头

#include <iostream>
#include <cstdio>

using namespace std;
const int N = 100010;

int d, n, m;
int a[N];

bool judge(int x)
{
    int tol = 0;
    int i = 0;
    int now = 0;

    while (i < n + 1)
    {
        i++;
        if (a[i] - a[now] < x) tol++;
        else now = i;
    }

    if (tol > m) return false;
    return true;
}

int main()
{
    cin >> d >> n >> m;

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

    int l = 0, r = d + 1, ans;
    while (l < r)
    {
        int mid = l + r >> 1;
        if (judge(mid)) l = mid + 1;
        else r = mid;
    }

    cout << l - 1 << endl;

    return 0;
}