Submission #894402

#	Time	Username	Problem	Language	Result	Execution time	Memory
894402		mychecksedad	Bigger segments (IZhO19_segments)	C++17	100 / 100	95 ms	61640 KiB

segments

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;

int n;
ll a[N], dp[N][2], pref[N];
vector<int> dps[N];
void solve(){
  cin >> n;
  for(int i = 1; i <= n; ++i) cin >> a[i];
  dp[0][0] = 0;
  dp[0][1] = 0;
  pref[0] = 0;
  for(int i = 1; i <= n; ++i) pref[i] = pref[i - 1] + a[i], dps[i].pb(0);

  for(int i = 1; i <= n; ++i){
    dp[i][0] = 0;
    dp[i][0] = dp[i - 1][0];
    dp[i][1] = dp[i - 1][1] + a[i];
    for(int j: dps[i]){
      ll s = pref[i] - pref[j];
      if(s >= dp[j][1]){
        if(dp[i][0] < dp[j][0] + 1){
          dp[i][0] = dp[j][0] + 1;
          dp[i][1] = s;
        }else if(dp[i][0] == dp[j][0] + 1) dp[i][1] = min(dp[i][1], s);
      }
    }
    int l = i + 1, r = n, cc = n + 1;
    while(l <= r){
      int m = l+r>>1;
      if(pref[m] - pref[i] >= dp[i][1]){
        cc = m;
        r = m - 1;
      }else l = m + 1;
    }
    dps[cc].pb(i);
  }
  cout << dp[n][0];
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

Compilation message (stderr)

segments.cpp: In function 'void solve()':
segments.cpp:38:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   38 |       int m = l+r>>1;
      |               ~^~
segments.cpp: In function 'int main()':
segments.cpp:52:15: warning: unused variable 'aa' [-Wunused-variable]
   52 |   int tt = 1, aa;
      |               ^~

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