Submission #1209082

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209082		matthew	Bouquet (EGOI24_bouquet)	C++20	100 / 100	77 ms	14548 KiB

Main

#include <stdio.h>
#include <algorithm>
#include <vector>

const int MAX_N = 2e5;

struct AIB {
  int n;
  int aib[MAX_N + 1];

  void init(int _n) { n = _n; }
  int query_max(int pref) {
    int res = 0;
    for(; pref > 0; pref &= pref - 1) {
      res = std::max(res, aib[pref]);
    }
    return res;
  }
  void update(int pos, int val) {
    for(; pos <= n; pos += pos & -pos) {
      aib[pos] = std::max(aib[pos], val);
    }
  }
};

int l[MAX_N], r[MAX_N];
AIB aib;
std::vector<int> updates[MAX_N + 1];
int dp[MAX_N];

void clamp_max(int &val, int max) {
  if(val > max) {
    val = max;
  }
}

int main() {
  int n;
  scanf("%d", &n);
  for(int i = 0; i < n; i++) {
    scanf("%d%d", &l[i], &r[i]);
    clamp_max(l[i], i);
    clamp_max(r[i], n - 1 - i);
  }

  aib.init(n);
  int res = 0;
  for(int i = 0; i < n; i++) {
    for(int x : updates[i]) {
      aib.update(x + 1, dp[x]);
    }
    int leftb = i + 1 - l[i];
    dp[i] = 1 + aib.query_max(leftb - 1);
    if(dp[i] > res) {
      res = dp[i];
    }
    updates[i + r[i] + 1].push_back(i);
  }

  printf("%d\n", res);

  return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |   scanf("%d", &n);
      |   ~~~~~^~~~~~~~~~
Main.cpp:41:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |     scanf("%d%d", &l[i], &r[i]);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 16 / 16
• Subtask 3: 28 / 28
• Subtask 4: 18 / 18
• Subtask 5: 30 / 30