Submission #678465

#	Time	Username	Problem	Language	Result	Execution time	Memory
678465		cig32	Measures (CEOI22_measures)	C++17	100 / 100	414 ms	52104 KiB

Main

#include "bits/stdc++.h"
using namespace std;
#define int long long
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 << ": "; }

struct segtree_mss {
  struct node {
    int premax = 0;
    int sufmax = 0;
    int totmax = 0;
    int sum = 0;
  };
  vector<node> st;
  int stok;
  void push_up(int idx) {
    st[idx].premax = max(st[2*idx+1].premax, st[2*idx+1].sum + st[2*idx+2].premax);
    st[idx].sufmax = max(st[2*idx+2].sufmax, st[2*idx+2].sum + st[2*idx+1].sufmax);
    st[idx].totmax = max({
      st[2*idx+1].totmax,
      st[2*idx+2].totmax,
      st[2*idx+1].sufmax + st[2*idx+2].premax
    });
    st[idx].sum = st[2*idx+1].sum + st[2*idx+2].sum;
  }
  void u(int l, int r, int tar, int idx, int val) {
    if(l == r) {
      st[idx].sum = val;
      st[idx].premax = max(val, 0ll);
      st[idx].sufmax = max(val, 0ll);
      st[idx].totmax = max(val, 0ll);
      return;
    }
    int mid = (l + r) >> 1;
    if(tar <= mid) u(l, mid, tar, 2*idx+1, val);
    else u(mid+1, r, tar, 2*idx+2, val);
    push_up(idx);
  }
  public:
  void resize(int k) {
    stok = k;
    st.resize(4*k + 10);
  }
  void point_assign(int i, int v) {
    u(1, stok, i, 0, v);
  }
  int query_mss() {
    return st[0].totmax;
  }
};

void solve(int tc) {
  int n, m, d;
  cin >> n >> m >> d;
  if(n > 0) {
    vector<int> v;
    for(int i=1; i<=n+m; i++) {
      int x;
      cin >> x;
      v.push_back(x);
      if(i <= n) continue;
      sort(v.begin(), v.end());
      int lb = 0, rb = 1e15;
      while(lb < rb) {
        double mid = (lb + rb) * 0.25;
        double mind = v[0] - mid;
        bool ok = 1;
        for(int i=1; i<v.size(); i++) {
          double res = v[i] - mid;
          double new_mind = max(mind + d, res);
          if(new_mind - mind < d || abs(new_mind - v[i]) > mid) {
            ok = 0; break;
          }
          mind = new_mind;
        }
        int realmid = (lb + rb) / 2;
        if(ok) rb = realmid;
        else lb = realmid + 1;
      }
      if(lb & 1) cout << lb / 2 << ".5" << " \n"[i == n+m];
      else cout << lb / 2 << " \n"[i == n+m];
    }
    return;
  }
  int dp[m+1];
  dp[0] = 0;
  int w[m+1], v[m+1];
  pair<int, int> ww[m+1];
  int pos[m+1];
  for(int i=1; i<=m; i++) {
    cin >> w[i];
    ww[i].first = w[i];
    ww[i].second = i;
  }
  sort(ww+1, ww+1+m);
  for(int i=1; i<=m; i++) pos[ww[i].second] = i;
  v[1] = 0;
  for(int i=2; i<=m; i++) v[i] = d - (w[i] - w[i-1]);
  segtree_mss stm;
  stm.resize(m);
  set<pair<int, int> > st;
  st.insert({4e9, -1});
  st.insert({-4e9, -1});
  for(int i=1; i<=m; i++) {
    if(st.empty()) {
      st.insert({w[i], i});
      cout << 0 << " \n"[i == m];
      continue;
    }
    auto it = st.lower_bound({w[i], i});
    if((*it).second != -1) {
      int ptr = (*it).second;
      stm.point_assign(pos[ptr], d - ((*it).first - w[i]));
    }
    it--;
    if((*it).second != -1) {
      stm.point_assign(pos[i], d - (w[i] - (*it).first));
    }
    else {
      stm.point_assign(pos[i], 0);
    }
    st.insert({w[i], i});
    int ans = stm.query_mss();
    cout << ans / 2 << (ans & 1 ? ".5" : "") << " \n"[i == m];
  }
}

int32_t main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
/*
>= 0 required
> 2*t: sad

bounding trick? (IOI 2021 candies)
1) point update the array
2) compute the answer given t

-> given many queries
Type 1: (x[i] < 0)  a[i]:=max(0, a[i]-x[i])
Type 2: (x[i] >= 0) a[i]:=a[i]+x[i], if a[i] > 2*t then SAD

Basically -> max subarray sum > 2*t: SAD else NOT SAD
*/

Compilation message (stderr)

Main.cpp: In function 'void solve(long long int)':
Main.cpp:85:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |         for(int i=1; i<v.size(); i++) {
      |                      ~^~~~~~~~~
Main.cpp:102:7: warning: variable 'dp' set but not used [-Wunused-but-set-variable]
  102 |   int dp[m+1];
      |       ^~
Main.cpp:104:15: warning: variable 'v' set but not used [-Wunused-but-set-variable]
  104 |   int w[m+1], v[m+1];
      |               ^

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 35 / 35
• Subtask 4: 41 / 41