Submission #805383

#	Time	Username	Problem	Language	Result	Execution time	Memory
805383		Essa2006	T-Covering (eJOI19_covering)	C++14	5 / 100	74 ms	47804 KiB

covering

#include<bits/stdc++.h>
using namespace std;
#define int long long 
#define endl '\n'
#define FF first
#define SS second
#define all(a) a.begin(), a.end()
#define mod (ll)(1000000007)
const int inf=1e9;
int n, m;
vector<int>Sz, Egs, Mn, P;
vector<vector<int>>A, B;

void pre(){
    Sz.clear(), Egs.clear(), Mn.clear(), A.clear(), B.clear();
    Sz.resize((n+5)*(m+5)), Egs=P=Sz, Mn.resize((n+5)*(m+5), inf), A.resize(n+5, vector<int>(m+5)), B=A;
    for(int i=1;i<(n+5)*(m+5);i++){
        P[i]=i;
    }
}
int trans(int i, int j){
    return i*(m+1)+j;
}
int find(int ind){
    if(ind==P[ind])
        return ind;
    P[ind]=find(P[ind]);
}

bool merge(int a, int b){
    int ga=find(a), gb=find(b);
    if(ga==gb)
        return 0;
    if(rand()&1)
        swap(a, b);
    P[ga]==gb;
    Sz[gb]+=Sz[ga];
    Egs[gb]+=Egs[ga];
    Mn[gb]=min(Mn[gb], Mn[ga]);
    return 1;
}
signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n>>m;
    pre();
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>A[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        B[i][0]=B[i][m+1]=2;
    }
    for(int j=1;j<=m;j++){
        B[0][j]=B[n+1][j]=2;
    }
    int q;
    cin>>q;
    while(q--){
        int i, j;
        cin>>i>>j;
        i++, j++;
        B[i][j]+=inf;
        B[i+1][j]++, B[i-1][j]++;
        B[i][j+1]++, B[i][j-1]++;
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(B[i][j]<inf)
                continue;
            int cur=trans(i, j);
            if(B[i+1][j]>=inf || B[i-1][j]>=inf || B[i][j-1]>=inf || B[i][j+1]>=inf)
                return cout<<"No", 0;
            Sz[cur]=1;
            Egs[cur]=B[i+1][j]+B[i-1][j]+B[i][j+1]+B[i][j-1]-4;
            if(B[i+1][j]==1)
                Mn[cur]=min(Mn[cur], A[i+1][j]);
            if(B[i-1][j]==1)
                Mn[cur]=min(Mn[cur], A[i-1][j]);
            if(B[i][j+1]==1)
                Mn[cur]=min(Mn[cur], A[i][j+1]);
            if(B[i][j-1]==1)
                Mn[cur]=min(Mn[cur], A[i][j-1]);
        }
    }
    for(int i=2;i<n;i++){
        for(int j=2;j<m;j++){
            vector<int>Cur;
            if(B[i+1][j]>=inf)
                Cur.push_back(trans(i+1, j));
            if(B[i-1][j]>=inf)
                Cur.push_back(trans(i-1, j));
            if(B[i][j+1]>=inf)
                Cur.push_back(trans(i, j+1));
            if(B[i][j-1]>=inf)
                Cur.push_back(trans(i, j-1));
            for(int l1=0;l1<Cur.size();l1++){
                for(int l2=0;l2<Cur.size();l2++){
                    if(l1==l2)
                        continue;
                    merge(Cur[l1], Cur[l2]);
                }
            }
        }
    }
    int ans=0;
    for(int i=0;i<P.size();i++){
        if(i!=find(i))
            continue;
        if(Egs[i]&1)
            Sz[i]/=0;
        if(Egs[i]/2>Sz[i])
            return cout<<"No", 0;
        else if(Egs[i]/2==Sz[i]-1){
            ans-=Mn[i];
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(B[i][j])
                ans+=A[i][j];
        }
    }
    cout<<ans;
}

Compilation message (stderr)

covering.cpp: In function 'bool merge(long long int, long long int)':
covering.cpp:36:10: warning: value computed is not used [-Wunused-value]
   36 |     P[ga]==gb;
covering.cpp: In function 'int main()':
covering.cpp:97:28: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |             for(int l1=0;l1<Cur.size();l1++){
      |                          ~~^~~~~~~~~~~
covering.cpp:98:32: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   98 |                 for(int l2=0;l2<Cur.size();l2++){
      |                              ~~^~~~~~~~~~~
covering.cpp:107:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |     for(int i=0;i<P.size();i++){
      |                 ~^~~~~~~~~
covering.cpp:111:18: warning: division by zero [-Wdiv-by-zero]
  111 |             Sz[i]/=0;
covering.cpp: In function 'long long int find(long long int)':
covering.cpp:27:11: warning: control reaches end of non-void function [-Wreturn-type]
   27 |     P[ind]=find(P[ind]);

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 30