Luogu P4105 [HEOI2014]南园满地堆轻絮

题目链接：​​传送门​​

明显的二分
简单的check
我的没有long long会炸掉50分

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <complex>
#include <algorithm>
#include <climits>
#include <queue>
#include <map>
#include <set>
#include <vector>
#include <iomanip>
#define
#define

using namespace std;
typedef long long ll;
int n, sa, sb, sc, sd, a[A], mod;
ll F(ll x) {
  return ((sa * x % mod * x % mod * x % mod + sb * x % mod * x % mod) % mod + (sc * x % mod + sd) % mod) % mod;
}
bool check(int x, int maxx = 1) {
  for (int i = 1; i <= n; i++) {
    maxx = max(maxx, a[i] - x);
    if (maxx > a[i] + x) return false;
  }
  return true;
}

int main(int argc, char const *argv[]) {
  cin >> n >> sa >> sb >> sc >> sd >> a[1] >> mod; a[0] = 0;
  for (int i = 2; i <= n; i++) a[i] = (F(a[i - 1]) + F(a[i - 2])) % mod;
  int l = 1, r = mod;
  while (l <= r) {
    int m = (l + r) >> 1;
    if (check(m)) r = m - 1;
    else l = m + 1;
  }
  cout << l << endl;
}