Submission #370428

#	Time	Username	Problem	Language	Result	Execution time	Memory
370428		casperwang	Bigger segments (IZhO19_segments)	C++14	13 / 100	1 ms	364 KiB

segments

#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
using namespace std;
#define debug(args...) kout("[ " + string(#args) + " ]", args)
void kout() { cerr << endl; }
template <class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ',kout(b...); }
template <class T> void pary(T L, T R) { while (L != R) cerr << *L << " \n"[++L==R]; }
 
const int MAXN = 500000;
int n;
int a[MAXN+1];
int pre[MAXN+1];
pii dp[MAXN+1];
pii ran[MAXN+1];
int ans;

bool solve(int id, int k) {
  int l = ran[k].ff, r = ran[k].ss;
  assert(dp[l].ff == dp[r].ff);
  while (l < r) {
    int mid = (l + r + 1) / 2;
    if (pre[id] - pre[mid] >= dp[mid].ss)
      l = mid;
    else
      r = mid - 1;
  }
  if (pre[id] - pre[l] >= dp[l].ss) {
    dp[id] = pii(dp[l].ff + 1, pre[id] - pre[l]);
    return true;
  }
  return false;
}
 
signed main() {
  ios_base::sync_with_stdio(0), cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++)
    cin >> a[i], pre[i] = pre[i-1] + a[i];
  for (int i = 1; i <= n; i++)
    ran[i] = pii(n+1, 0);
  for (int i = 1; i <= n; i++) {
    if (!solve(i, dp[i-1].ff))
      solve(i, dp[i-1].ff-1);
    int nx = dp[i].ff;
    ran[nx].ff = min(ran[nx].ff, i);
    ran[nx].ss = max(ran[nx].ss, i);
  }
  cout << dp[n].ff << '\n';
}

• Subtask 1: 13 / 13
• Subtask 2: 0 / 14
• Subtask 3: 0 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27