Submission #720590

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
720590	2023-04-08T15:02:58 Z	Ahmed57	Mag (COCI16_mag)	C++14	84 / 120	1049 ms	262144 KB

//LCA
#include <bits/stdc++.h>

using namespace std;
#define int long long
vector<int> adj[1000001];
long long ma[1000001];
long long lon[1000001];
int n ;
void calc(int i,int pr){
    long long ch = (ma[i]==1?1:0);
    for(auto j:adj[i]){
        if(j!=pr){
            calc(j,i);
            if(ma[i]==1)ch = max(ch,lon[j]+1);
        }
    }
    lon[i] = ch;
}
long long maa = 0;
void dfs(int i,int pr){
    maa = max(maa,lon[i]);
    for(auto j:adj[i]){
        if(j==pr)continue;
        dfs(j,i);
    }
    if(ma[i]==1){
        long long firstma = 0 , secondma = 0;
        for(auto j:adj[i]){
            if(j==pr)continue;
            if(firstma<=lon[j]){
                secondma = firstma;
                firstma = lon[j];
            }else if(secondma<=lon[j]){
                secondma = lon[j];
            }
        }
        maa = max(maa,firstma+secondma+1);
    }
}
bool ss = 0;
void reroor(int i,int pr,int cnt){
    if(ma[i]==2){
        long long firstma = cnt , secondma = 0;
        for(auto j:adj[i]){
            if(j==pr)continue;
            if(firstma<=lon[j]){
                secondma = firstma;
                firstma = lon[j];
            }else if(secondma<=lon[j]){
                secondma = lon[j];
            }
        }
        if(firstma==secondma&&firstma==maa){
            ss = 1;
        }
    }
    vector<int> pref,suf,ch;
    int mm= 0;
    for(auto j:adj[i]){
        if(j==pr)continue;
        mm = max(mm,lon[j]);
        pref.push_back(mm);
        ch.push_back(j);
    }
    mm = cnt;suf.push_back(mm);
    reverse(ch.begin(),ch.end());
    for(auto j:ch){
        mm = max(mm,lon[j]);
        suf.push_back(mm);
    }
    reverse(suf.begin(),suf.end());
    reverse(ch.begin(),ch.end());
    for(int j = 0;j<ch.size();j++){
        reroor(ch[j],i,(ma[i]==1?max(suf[j+1],(j==0?0:pref[j-1]))+1:0));
    }
}
signed main(){
    cin>>n;
    for(int i = 0;i<n-1;i++){
        int a,b;cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    long long mi = 1e18;
    for(int i = 0;i<n;i++){
        cin>>ma[i+1];
        mi = min(mi,ma[i+1]);
    }
    calc(1,0);
    dfs(1,0);
    reroor(1,0,0);
    if(mi!=1)cout<<mi<<"/"<<1<<endl;
    else if(ss) cout<<2<<"/"<<2*maa+1<<endl;
    else cout<<1<<"/"<<maa<<endl;
}

Compilation message

mag.cpp: In function 'void reroor(long long int, long long int, long long int)':
mag.cpp:74:20: 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]
   74 |     for(int j = 0;j<ch.size();j++){
      |                   ~^~~~~~~~~~

Subtask #1
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	14 ms	23764 KB	Output is correct
2	Correct	13 ms	23828 KB	Output is correct

Subtask #2
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	13 ms	23764 KB	Output is correct
2	Correct	13 ms	23756 KB	Output is correct

Subtask #3
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	899 ms	174076 KB	Output is correct

Subtask #4
0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	23764 KB	Output is correct
2	Runtime error	989 ms	262144 KB	Execution killed with signal 9
3	Halted	0 ms	0 KB	-

Subtask #5
0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Runtime error	1016 ms	262144 KB	Execution killed with signal 9
2	Halted	0 ms	0 KB	-

Subtask #6
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	910 ms	70608 KB	Output is correct
2	Correct	660 ms	58832 KB	Output is correct

Subtask #7
0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	956 ms	84240 KB	Output is correct
2	Correct	143 ms	29072 KB	Output is correct
3	Runtime error	1049 ms	262144 KB	Execution killed with signal 9
4	Halted	0 ms	0 KB	-

Subtask #8
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	145 ms	29004 KB	Output is correct
2	Correct	940 ms	73768 KB	Output is correct
3	Correct	606 ms	57868 KB	Output is correct

Subtask #9
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	854 ms	73840 KB	Output is correct
2	Correct	964 ms	70328 KB	Output is correct

Subtask #10
12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	927 ms	72632 KB	Output is correct
2	Correct	624 ms	51844 KB	Output is correct