oj.uz

Submission #720610

# Submission time Handle Problem Language Result Execution time Memory
720610 2023-04-08T15:34:41 Z Ahmed57 Mag (COCI16_mag) C++14
120 / 120
 1065 ms 180384 KB 
#include <bits/stdc++.h>

using namespace std;
vector<int> adj[1000006];
int ma[1000006];
int lon[1000006];
int pref[1000006];
int suf[1000006];vector<int> ch;
int n ;
void calc(int i,int pr){
    int 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;
}
int 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){
        int 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;int mm = 0;
void reroor(int i,int pr,int cnt){
    if(ma[i]==2){
        int 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;
        }
    }
    ch.clear();
    mm = 0;
    for(auto j:adj[i]){
        if(j==pr)continue;
        pref[j] = mm;
        mm = max(mm,lon[j]);
        ch.push_back(j);
    }
    mm = cnt;
    reverse(ch.begin(),ch.end());
    for(auto j:ch){
        suf[j] = mm;
        mm = max(mm,lon[j]);
    }
    for(auto j:adj[i]){
        if(j==pr)continue;
        reroor(j,i,(ma[i]==1?max(suf[j],pref[j])+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);
    }
    int mi = 1e9;
    for(int i = 0;i<n;i++){
        cin>>ma[i+1];
        mi = min(mi,ma[i+1]);
    }
    if(mi!=1){
        cout<<mi<<"/"<<1<<endl;
        return 0;
    }
    calc(1,0);
    dfs(1,0);
    reroor(1,0,0);
    if(ss) cout<<2<<"/"<<2*maa+1<<endl;
    else cout<<1<<"/"<<maa<<endl;
}

Subtask #1
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 16 ms 23848 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23764 KB Output is correct
2 Correct 13 ms 23792 KB Output is correct

Subtask #3
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 878 ms 105104 KB Output is correct

Subtask #4
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23776 KB Output is correct
2 Correct 1031 ms 178896 KB Output is correct

Subtask #5
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1045 ms 176444 KB Output is correct

Subtask #6
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 912 ms 70488 KB Output is correct
2 Correct 678 ms 58264 KB Output is correct

Subtask #7
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 959 ms 73028 KB Output is correct
2 Correct 131 ms 28540 KB Output is correct
3 Correct 1065 ms 180384 KB Output is correct

Subtask #8
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 130 ms 28504 KB Output is correct
2 Correct 865 ms 71396 KB Output is correct
3 Correct 694 ms 47828 KB Output is correct

Subtask #9
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 855 ms 68808 KB Output is correct
2 Correct 937 ms 69916 KB Output is correct

Subtask #10
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 937 ms 71384 KB Output is correct
2 Correct 660 ms 47812 KB Output is correct