oj.uz

Submission #356263

# Submission time Handle Problem Language Result Execution time Memory
356263 2021-01-23T08:48:34 Z achibasadzishvili Islands (IOI08_islands) C++11
70 / 100
 642 ms 131076 KB 
#include<bits/stdc++.h>
#define ll long long
#define int long long
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define N 1000002
using namespace std;
int n,p[N],l[N],fix[N],F[N],k,c[N],len;
long long mx[N],ans,pas;
vector<pair<int,int> >v[N];
vector<int>g,all,dis;
void dfs(int x){
    if(F[x])return;
    all.pb(x);
    F[x] = 1;
    for(int i=0; i<v[x].size(); i++)
        dfs(v[x][i].f);
}
void findc(int x,int par){
    if(fix[x]){
        g.pb(x);
        dis.pb(l[par]);
        k = 1;
        return;
    }
    g.pb(x);
    fix[x] = 1;
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i].s != par){
            dis.pb(l[v[x][i].s]);
            findc(v[x][i].f , v[x][i].s);
            if(k)return;
            dis.pop_back();
        }
    g.pop_back();
}
void findmx(int x,int par){
    for(int i=0; i<v[x].size(); i++){
        if(v[x][i].s != par && !c[v[x][i].f]){
            findmx(v[x][i].f , v[x][i].s);
            ans = max(ans , mx[x] + mx[v[x][i].f] + l[v[x][i].s]);
            mx[x] = max(mx[x] , mx[v[x][i].f] + l[v[x][i].s]);
        }
    }
}
main(){
    ios::sync_with_stdio(false);
    cin >> n;
    
    for(int i=1; i<=n; i++){
        cin >> p[i] >> l[i];
        v[p[i]].pb(mp(i , i));
        v[i].pb(mp(p[i] , i));
    }
    ll cur,cur2,pre;
    for(int s=1; s<=n; s++){
        if(F[s])continue;
        len = 0;
        ans = 0;
        k = 0;
        all.clear();
        dfs(s);
        g.clear();
        dis.clear();
        findc(s , 0);
        vector<int>cyc,d;
        for(int i=0; i<g.size(); i++){
            if(g[i] == g[(int)g.size() - 1]){
                for(int j=i+1; j<g.size(); j++){
                    cyc.pb(g[j]);
                    d.pb(dis[j - 1]);
                    c[g[j]] = 1;
                }
                break;
            }
        }
        for(int i=0; i<cyc.size(); i++){
            findmx(cyc[i] , 0);
            len += d[i];
        }
        cur = mx[cyc[0]];
        cur2 = mx[cyc[0]];
        pre = 0;
        for(int i=1; i<cyc.size(); i++){
            pre += d[i];
            ans = max(ans , cur + mx[cyc[i]] + pre);
            ans = max(ans , cur2 + len + mx[cyc[i]] - pre);
            cur = max(cur , mx[cyc[i]] - pre);
            cur2 = max(cur2 , mx[cyc[i]] + pre);
        }
        pas += ans;
    }
    
    cout << pas << '\n';
    
}

Compilation message

islands.cpp: In function 'void dfs(long long int)':
islands.cpp:18:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |     for(int i=0; i<v[x].size(); i++)
      |                  ~^~~~~~~~~~~~
islands.cpp: In function 'void findc(long long int, long long int)':
islands.cpp:30:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i=0; i<v[x].size(); i++)
      |                  ~^~~~~~~~~~~~
islands.cpp: In function 'void findmx(long long int, long long int)':
islands.cpp:40:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |     for(int i=0; i<v[x].size(); i++){
      |                  ~^~~~~~~~~~~~
islands.cpp: At global scope:
islands.cpp:48:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   48 | main(){
      |      ^
islands.cpp: In function 'int main()':
islands.cpp:69:23: 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]
   69 |         for(int i=0; i<g.size(); i++){
      |                      ~^~~~~~~~~
islands.cpp:71:33: 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]
   71 |                 for(int j=i+1; j<g.size(); j++){
      |                                ~^~~~~~~~~
islands.cpp:79:23: 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]
   79 |         for(int i=0; i<cyc.size(); i++){
      |                      ~^~~~~~~~~~~
islands.cpp:86:23: 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]
   86 |         for(int i=1; i<cyc.size(); i++){
      |                      ~^~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 23916 KB Output is correct
2 Correct 16 ms 23916 KB Output is correct
3 Correct 17 ms 23916 KB Output is correct
4 Correct 16 ms 23916 KB Output is correct
5 Correct 16 ms 23916 KB Output is correct
6 Correct 18 ms 23916 KB Output is correct
7 Correct 17 ms 23916 KB Output is correct
8 Correct 18 ms 23916 KB Output is correct
9 Correct 16 ms 23916 KB Output is correct
10 Correct 16 ms 23916 KB Output is correct
11 Correct 16 ms 23916 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 24056 KB Output is correct
2 Correct 17 ms 24044 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 24044 KB Output is correct
2 Correct 19 ms 24524 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 25708 KB Output is correct
2 Correct 40 ms 29796 KB Output is correct
3 Correct 29 ms 26600 KB Output is correct
4 Correct 22 ms 25196 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 31464 KB Output is correct
2 Correct 57 ms 35320 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 138 ms 47196 KB Output is correct
2 Correct 119 ms 52720 KB Output is correct
3 Correct 152 ms 68320 KB Output is correct

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 178 ms 63748 KB Output is correct
2 Correct 244 ms 105812 KB Output is correct
3 Correct 309 ms 110896 KB Output is correct
4 Runtime error 326 ms 131076 KB Execution killed with signal 9

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 388 ms 115708 KB Output is correct
2 Runtime error 642 ms 131076 KB Execution killed with signal 9
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 404 ms 131072 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -