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Submission #901677

# Submission time Handle Problem Language Result Execution time Memory
901677 2024-01-09T22:41:05 Z NourWael Nafta (COI15_nafta) C++17
100 / 100
 861 ms 125264 KB 
#include <bits/stdc++.h>
using namespace std;
int const mxN = 2e3+2;
int n,m,k, a[mxN][mxN], dp[mxN][mxN], c = 0;
int inC[mxN][mxN], first_col[mxN*mxN], cost[mxN*mxN];
bool vis[mxN][mxN];
vector<int> pref [mxN];
vector<int> col [mxN];

bool valid ( int i, int j ) {
   if(i<0 || j<0 || i==n || j==m) return false;
   if(a[i][j]==-1 || vis[i][j]) return false;
   vis[i][j] = 1;
   return true;
}

int dfs ( int i, int j) {
  int ans = a[i][j];
  inC[i][j] = c;
  first_col[c] = min ( j, first_col[c] );
  if( valid(i+1,j) ) ans+=dfs(i+1,j);
  if( valid(i,j+1) ) ans+=dfs(i,j+1);
  if( valid(i-1,j) ) ans+=dfs(i-1,j);
  if( valid(i,j-1) ) ans+=dfs(i,j-1);
  return ans;
}

void solve ( int l, int r, int indl , int indr, int sz ) {
  if(l>r) return;
  int mid = (l+r)/2, ind = mid, maxi = 0;

  for(int i=indl; i<=min(indr, mid-1); i++) {
   int ans = dp[i][sz-1];
   int d = upper_bound(col[mid].begin(),col[mid].end(),i) - col[mid].begin();
   if(d!=col[mid].size()) { ans += pref[mid].back(); if(d) ans -= pref[mid][d-1]; }
   
   if(ans>maxi) {
    maxi = ans;
    ind = i;
   }
  }

  dp[mid][sz] = maxi;
  solve(l,mid-1, indl, ind, sz), solve(mid+1, r, ind, indr, sz);

}
signed main (){
     ios::sync_with_stdio(false);
     cin.tie(nullptr);
     cout.tie(nullptr);
     cin>>n>>m;
     for(int i=0; i<n; i++) 
      for(int j=0; j<m; j++) {
        char x; cin>>x;
        if(x=='.') a[i][j] = -1;
        else a[i][j] = x-'0'; 
      }

     for(int i=0; i<n; i++) 
      for(int j=0; j<m; j++) 
        if(!vis[i][j] && a[i][j]>-1) {
          vis[i][j] = 1;
          c++;
          first_col[c] = 1e9;
          cost[c] =  dfs(i,j);
        }
      
     for(int j=0; j<m; j++) {
      set<int> st;
      int ans = 0;
      for(int i=0; i<n; i++) {
        if(st.find(inC[i][j])==st.end() && a[i][j]>-1 ) { ans+=cost[inC[i][j]]; st.insert(inC[i][j]); }
      }
      dp[j][1] = ans;
     }
     
     for(int j=0; j<m; j++) {
      set<int>st;
      for(int i=0; i<n; i++) if(a[i][j]>-1) st.insert(inC[i][j]);
      vector<pair<int,int>> v;
      for(auto it:st ) v.push_back({first_col[it], it});
      sort(v.begin(),v.end());
      for(int h=0; h<v.size(); h++) {
        if(col[j].size() && col[j].back()==v[h].first) pref[j].back()+=cost[v[h].second];
        else { 
          col[j].push_back(v[h].first), pref[j].push_back(cost[v[h].second]);
          if(pref[j].size()>1) pref[j].back() += pref[j][pref[j].size()-2];
        }
      }  
     }
    for(int i=2; i<=m; i++) solve(0,m-1, 0, m-1, i);

    for(int i=1; i<=m; i++) {
      int maxi = 0;
      for(int h=0; h<m; h++) maxi = max ( maxi, dp[h][i]);
      cout<<maxi<<'\n';
    }
  return 0;
}

Compilation message

nafta.cpp: In function 'void solve(int, int, int, int, int)':
nafta.cpp:35:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |    if(d!=col[mid].size()) { ans += pref[mid].back(); if(d) ans -= pref[mid][d-1]; }
      |       ~^~~~~~~~~~~~~~~~~
nafta.cpp: In function 'int main()':
nafta.cpp:83:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |       for(int h=0; h<v.size(); h++) {
      |                    ~^~~~~~~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9048 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 1 ms 9052 KB Output is correct
4 Correct 2 ms 9012 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct

Subtask #2
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9048 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 1 ms 9052 KB Output is correct
4 Correct 2 ms 9012 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 11 ms 15704 KB Output is correct
8 Correct 14 ms 15732 KB Output is correct
9 Correct 10 ms 17240 KB Output is correct
10 Correct 11 ms 15708 KB Output is correct
11 Correct 13 ms 15720 KB Output is correct
12 Correct 13 ms 15708 KB Output is correct

Subtask #3
66.0 / 66.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9048 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 1 ms 9052 KB Output is correct
4 Correct 2 ms 9012 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 11 ms 15704 KB Output is correct
8 Correct 14 ms 15732 KB Output is correct
9 Correct 10 ms 17240 KB Output is correct
10 Correct 11 ms 15708 KB Output is correct
11 Correct 13 ms 15720 KB Output is correct
12 Correct 13 ms 15708 KB Output is correct
13 Correct 507 ms 58620 KB Output is correct
14 Correct 644 ms 58980 KB Output is correct
15 Correct 473 ms 125264 KB Output is correct
16 Correct 488 ms 59988 KB Output is correct
17 Correct 861 ms 59300 KB Output is correct
18 Correct 758 ms 59328 KB Output is correct