oj.uz

Submission #952478

# Submission time Handle Problem Language Result Execution time Memory
952478 2024-03-24T05:12:52 Z nguyennh Bigger segments (IZhO19_segments) C++14
37 / 100
 258 ms 142300 KB 
#include<bits/stdc++.h>
#define el '\n'
using namespace std ;

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());

const int64_t inf = 1e18;
const int MN = 5e5 + 5;

int a[MN] , n;

namespace sub_trau{
  int x[25] , ans = 0;
  
  void backtrack(int k){
    if (k > n - 1){
      int cur = 0 , sum = 0 , cnt = 0;
      bool check = true;
      for ( int i = 1 ; i <= n; i++ ){
        sum += a[i];
        if (x[i] == 1){
          if (sum < cur){
            check = false;
            break;
          }
          cnt++;
          cur = sum;
          sum = 0;
        }
      }
      if (check) ans = max(ans , cnt);
      return;
    }
    for ( int i = 0 ; i <= 1 ; i++ ){
      x[k] = i;
      backtrack(k + 1);
    }
  }
  
  void solve(){
    x[n] = 1;
    backtrack(1);
    cout << ans;
  }
}

namespace sub3{
  void solve(){
    vector<int64_t> pref(n + 5);
    for ( int i = 1 ; i <= n ; i++ ) pref[i] = pref[i - 1] + a[i];
    vector<vector<int64_t>> dp(n + 5 , vector<int64_t>(n + 5)) , suf(n + 5 , vector<int64_t>(n + 5 , 0));
    dp[1][1] = 1;
    suf[1][1] = 1;
    for ( int i = n ; i >= 1 ; i-- ) suf[1][i] = min(suf[1][i + 1] , suf[1][i]);
    for ( int i = 1 ; i <= n ; i++ ){
      for ( int j = i ; j >= 1 ; j-- ){
        int l = 1 , r = j , pos = -1;
        while (l <= r){
          int mid = l + r >> 1;
          if (pref[j - 1] - pref[mid - 1] <= pref[i] - pref[j - 1]){
            pos = mid;
            r = mid - 1;
          }
          else l = mid + 1;
        } 
        assert(pos != -1);
        if (pos == 1) pos--;
        if (!pos){
          dp[i][j] = max(dp[i][j] , suf[j - 1][pos] + 1);
        }
        else {
          if (suf[j - 1][pos]) dp[i][j] = max(dp[i][j] , suf[j - 1][pos] + 1);
        }
      }
      for ( int j = i ; j >= 0 ; j-- ) suf[i][j] = max(suf[i][j + 1] , dp[i][j]);
    }
    int64_t ans = 0;
    for ( int i = 1 ; i <= n ; i++ ){
      ans = max(ans , dp[n][i]);
    }
    cout << ans;
  }
}

namespace sub_final{
  struct Segtri{
    vector<int64_t> st;
    
    Segtri(int n) : st(4 * n + 5) {
      for ( int i = 1 ; i <= 4 * n ; i++ ) st[i] = inf;
    };
    
    void update(int id , int l , int r , int i , int val){
      if (i < l || i > r) return;
      if (l == r){
        st[id] = val;
        return;
      }
      int mid = l + r >> 1;
      update(id << 1 , l , mid , i , val);
      update(id << 1 | 1 , mid + 1 , r , i , val);
      st[id] = min(st[id << 1] , st[id << 1 | 1]);
    }
    
    int walk(int id , int l , int r , int64_t val){
      if (st[id] > val) return -1;
      if (l == r) return l;
      int mid = l + r >> 1;
      if (st[id << 1] <= val) return walk(id << 1 , l , mid , val);
      return walk(id << 1 | 1 , mid + 1 , r , val);
    }
  };
  
  void solve(){
    vector<int64_t> pref(n + 5) , dp(n + 5);
    reverse(a + 1 , a + n + 1);
    for ( int i = n ; i >= 1 ; i-- ) pref[i] = pref[i + 1] + a[i];
    Segtri it(n + 1);
    it.update(1 , 1 , n + 1 , n + 1 , 0);
    for ( int i = n ; i >= 1 ; i-- ){
      int pos = it.walk(1 , 1 , n + 1 , pref[i]);
      dp[i] = dp[pos] + 1;
      it.update(1 , 1 , n + 1 , i , 2 * pref[i] - pref[pos]);
    }
    cout << dp[1];
  }
}

int32_t main (){
//  freopen("segments.inp" , "r" , stdin);
//  freopen("segments.out" , "w" , stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  for ( int i = 1 ; i <= n ; i++ ) cin >> a[i];
  if (n <= 20){
    sub_trau::solve();
    return 0;
  }
  if (n <= 3000){
    sub3::solve();
    return 0;
  }
  sub_final::solve();
}

Compilation message

segments.cpp: In function 'void sub3::solve()':
segments.cpp:59:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   59 |           int mid = l + r >> 1;
      |                     ~~^~~
segments.cpp: In member function 'void sub_final::Segtri::update(int, int, int, int, int)':
segments.cpp:99:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   99 |       int mid = l + r >> 1;
      |                 ~~^~~
segments.cpp: In member function 'int sub_final::Segtri::walk(int, int, int, int64_t)':
segments.cpp:108:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  108 |       int mid = l + r >> 1;
      |                 ~~^~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 4 ms 348 KB Output is correct
5 Correct 6 ms 348 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 5 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 6 ms 348 KB Output is correct
12 Correct 5 ms 348 KB Output is correct
13 Correct 7 ms 600 KB Output is correct
14 Correct 7 ms 348 KB Output is correct
15 Correct 5 ms 348 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 4 ms 348 KB Output is correct
5 Correct 6 ms 348 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 5 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 6 ms 348 KB Output is correct
12 Correct 5 ms 348 KB Output is correct
13 Correct 7 ms 600 KB Output is correct
14 Correct 7 ms 348 KB Output is correct
15 Correct 5 ms 348 KB Output is correct
16 Correct 5 ms 4444 KB Output is correct
17 Correct 4 ms 4444 KB Output is correct
18 Correct 5 ms 4440 KB Output is correct
19 Correct 4 ms 4444 KB Output is correct
20 Correct 5 ms 4444 KB Output is correct
21 Correct 5 ms 4444 KB Output is correct
22 Correct 6 ms 2908 KB Output is correct
23 Correct 2 ms 1884 KB Output is correct
24 Correct 6 ms 4444 KB Output is correct
25 Correct 5 ms 4444 KB Output is correct
26 Correct 4 ms 4444 KB Output is correct
27 Correct 4 ms 4444 KB Output is correct
28 Correct 5 ms 4444 KB Output is correct
29 Correct 4 ms 4444 KB Output is correct
30 Correct 5 ms 4444 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 4 ms 348 KB Output is correct
5 Correct 6 ms 348 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 5 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 6 ms 348 KB Output is correct
12 Correct 5 ms 348 KB Output is correct
13 Correct 7 ms 600 KB Output is correct
14 Correct 7 ms 348 KB Output is correct
15 Correct 5 ms 348 KB Output is correct
16 Correct 5 ms 4444 KB Output is correct
17 Correct 4 ms 4444 KB Output is correct
18 Correct 5 ms 4440 KB Output is correct
19 Correct 4 ms 4444 KB Output is correct
20 Correct 5 ms 4444 KB Output is correct
21 Correct 5 ms 4444 KB Output is correct
22 Correct 6 ms 2908 KB Output is correct
23 Correct 2 ms 1884 KB Output is correct
24 Correct 6 ms 4444 KB Output is correct
25 Correct 5 ms 4444 KB Output is correct
26 Correct 4 ms 4444 KB Output is correct
27 Correct 4 ms 4444 KB Output is correct
28 Correct 5 ms 4444 KB Output is correct
29 Correct 4 ms 4444 KB Output is correct
30 Correct 5 ms 4444 KB Output is correct
31 Correct 251 ms 141872 KB Output is correct
32 Correct 200 ms 142088 KB Output is correct
33 Correct 222 ms 141992 KB Output is correct
34 Correct 245 ms 142092 KB Output is correct
35 Correct 244 ms 142300 KB Output is correct
36 Correct 228 ms 141908 KB Output is correct
37 Correct 153 ms 98752 KB Output is correct
38 Correct 94 ms 63464 KB Output is correct
39 Correct 229 ms 141908 KB Output is correct
40 Correct 232 ms 141904 KB Output is correct
41 Correct 207 ms 141908 KB Output is correct
42 Correct 216 ms 141904 KB Output is correct
43 Correct 258 ms 142072 KB Output is correct
44 Correct 207 ms 141908 KB Output is correct
45 Correct 210 ms 142080 KB Output is correct

Subtask #4
0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 4 ms 348 KB Output is correct
5 Correct 6 ms 348 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 5 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 6 ms 348 KB Output is correct
12 Correct 5 ms 348 KB Output is correct
13 Correct 7 ms 600 KB Output is correct
14 Correct 7 ms 348 KB Output is correct
15 Correct 5 ms 348 KB Output is correct
16 Correct 5 ms 4444 KB Output is correct
17 Correct 4 ms 4444 KB Output is correct
18 Correct 5 ms 4440 KB Output is correct
19 Correct 4 ms 4444 KB Output is correct
20 Correct 5 ms 4444 KB Output is correct
21 Correct 5 ms 4444 KB Output is correct
22 Correct 6 ms 2908 KB Output is correct
23 Correct 2 ms 1884 KB Output is correct
24 Correct 6 ms 4444 KB Output is correct
25 Correct 5 ms 4444 KB Output is correct
26 Correct 4 ms 4444 KB Output is correct
27 Correct 4 ms 4444 KB Output is correct
28 Correct 5 ms 4444 KB Output is correct
29 Correct 4 ms 4444 KB Output is correct
30 Correct 5 ms 4444 KB Output is correct
31 Correct 251 ms 141872 KB Output is correct
32 Correct 200 ms 142088 KB Output is correct
33 Correct 222 ms 141992 KB Output is correct
34 Correct 245 ms 142092 KB Output is correct
35 Correct 244 ms 142300 KB Output is correct
36 Correct 228 ms 141908 KB Output is correct
37 Correct 153 ms 98752 KB Output is correct
38 Correct 94 ms 63464 KB Output is correct
39 Correct 229 ms 141908 KB Output is correct
40 Correct 232 ms 141904 KB Output is correct
41 Correct 207 ms 141908 KB Output is correct
42 Correct 216 ms 141904 KB Output is correct
43 Correct 258 ms 142072 KB Output is correct
44 Correct 207 ms 141908 KB Output is correct
45 Correct 210 ms 142080 KB Output is correct
46 Correct 18 ms 5720 KB Output is correct
47 Correct 20 ms 5976 KB Output is correct
48 Incorrect 23 ms 6236 KB Output isn't correct
49 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 4 ms 348 KB Output is correct
5 Correct 6 ms 348 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 5 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 6 ms 348 KB Output is correct
12 Correct 5 ms 348 KB Output is correct
13 Correct 7 ms 600 KB Output is correct
14 Correct 7 ms 348 KB Output is correct
15 Correct 5 ms 348 KB Output is correct
16 Correct 5 ms 4444 KB Output is correct
17 Correct 4 ms 4444 KB Output is correct
18 Correct 5 ms 4440 KB Output is correct
19 Correct 4 ms 4444 KB Output is correct
20 Correct 5 ms 4444 KB Output is correct
21 Correct 5 ms 4444 KB Output is correct
22 Correct 6 ms 2908 KB Output is correct
23 Correct 2 ms 1884 KB Output is correct
24 Correct 6 ms 4444 KB Output is correct
25 Correct 5 ms 4444 KB Output is correct
26 Correct 4 ms 4444 KB Output is correct
27 Correct 4 ms 4444 KB Output is correct
28 Correct 5 ms 4444 KB Output is correct
29 Correct 4 ms 4444 KB Output is correct
30 Correct 5 ms 4444 KB Output is correct
31 Correct 251 ms 141872 KB Output is correct
32 Correct 200 ms 142088 KB Output is correct
33 Correct 222 ms 141992 KB Output is correct
34 Correct 245 ms 142092 KB Output is correct
35 Correct 244 ms 142300 KB Output is correct
36 Correct 228 ms 141908 KB Output is correct
37 Correct 153 ms 98752 KB Output is correct
38 Correct 94 ms 63464 KB Output is correct
39 Correct 229 ms 141908 KB Output is correct
40 Correct 232 ms 141904 KB Output is correct
41 Correct 207 ms 141908 KB Output is correct
42 Correct 216 ms 141904 KB Output is correct
43 Correct 258 ms 142072 KB Output is correct
44 Correct 207 ms 141908 KB Output is correct
45 Correct 210 ms 142080 KB Output is correct
46 Correct 18 ms 5720 KB Output is correct
47 Correct 20 ms 5976 KB Output is correct
48 Incorrect 23 ms 6236 KB Output isn't correct
49 Halted 0 ms 0 KB -