Submission #910700

#	Time	Username	Problem	Language	Result	Execution time	Memory
910700		cig32	Seesaw (JOI22_seesaw)	C++17	34 / 100	2057 ms	72060 KiB

seesaw

#include "bits/stdc++.h"
using namespace std;
#define int long long
#define double long double
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
  if(p==0) return 1 % MOD;
  int r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
int inv(int b) { 
  return bm(b, MOD-2);
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
static void run_with_stack_size(void (*func)(void), size_t stsize) {
  char *stack, *send;
  stack = (char *)malloc(stsize);
  send = stack + stsize - 16;
  send = (char *)((uintptr_t)send / 16 * 16);
  asm volatile(
    "mov %%rsp, (%0)\n"
    "mov %0, %%rsp\n"
    :
    : "r"(send));
  func();
  asm volatile("mov (%0), %%rsp\n" : : "r"(send));
  free(stack);
}
void solve(int tc) { 
  int n;
  cin >> n;
  int a[n+1];
  for(int i=1; i<=n; i++) {
    cin >> a[i];
  }
  int ps[n+1];
  ps[0] = 0;
  for(int i=1; i<=n; i++) ps[i] = ps[i-1] + a[i];
  vector<pair<double, pair<int,int>> > vt;
  for(int i=1; i<=n; i++) {
    for(int j=i; j<=n; j++) {
      double bi = (ps[j] - ps[i-1]) * 1.0 / (j - i + 1);
      vt.push_back({bi, {i, j}});
    }
  }
  sort(vt.begin(), vt.end());
  bool dp[n+1][n+1], init[n+1][n+1];
  for(int i=0; i<=n; i++) {
    for(int j=0; j<=n; j++) {
      init[i][j] = dp[i][j] = 0;
    }
  }
  int j = -1;
  double ans = 1e18;
  for(int i=0; i<vt.size(); i++) {  
    j = max(j, i - 1);
    double l = vt[i].first;
    if(i > 0) {
      int l = vt[i-1].second.first;
      int r = vt[i-1].second.second;
      init[l][r] = 0;
    }
    bool good = 0;
    while(1) {
      for(int k=1; k<=n; k++) for(int l=k; l<=n; l++) dp[k][l] = 0;
      for(int k=1; k<=n; k++) {
        dp[k][k] = init[k][k];
      }
      for(int len=2; len<=n; len++) {
        for(int k=1; k+len-1<=n; k++) {
          dp[k][k+len-1] = init[k][k+len-1] && (dp[k+1][k+len-1] || dp[k][k+len-2]);
        }
      }
      if(dp[1][n]) {
        good = 1;
        break;
      }
      if(j + 1 < vt.size()) {
        j++;
        int l = vt[j].second.first;
        int r = vt[j].second.second;
        init[l][r] = 1;
      }
      else break;

    }
    if(good) {
      ans = min(ans, vt[j].first - vt[i].first);
    }
  }
  cout << fixed << setprecision(10) << ans << '\n';
}

void uwu() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
int32_t main() {
  #ifdef ONLINE_JUDGE
  uwu();
  #endif
  #ifndef ONLINE_JUDGE
  run_with_stack_size(uwu, 1024 * 1024 * 1024); // run with a 1 GiB stack
  #endif
}
/*
g++ A.cpp -std=c++17 -O2 -o A
./A < input.txt
*/

Compilation message (stderr)

seesaw.cpp: In function 'void solve(long long int)':
seesaw.cpp:64:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long double, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |   for(int i=0; i<vt.size(); i++) {
      |                ~^~~~~~~~~~
seesaw.cpp:87:16: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long double, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |       if(j + 1 < vt.size()) {
      |          ~~~~~~^~~~~~~~~~~
seesaw.cpp:66:12: warning: unused variable 'l' [-Wunused-variable]
   66 |     double l = vt[i].first;
      |            ^

• Subtask 1: 1 / 1
• Subtask 2: 33 / 33
• Subtask 3: 0 / 33
• Subtask 4: 0 / 33