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Submission #87180

# Submission time Handle Problem Language Result Execution time Memory
87180 2018-11-29T22:26:40 Z nikolapesic2802 Zagrade (COI17_zagrade) C++14
100 / 100
 972 ms 65276 KB 
/*
    - Decompose the tree using centroid decomposition.
    - Do something super similar to the example problem in this post: https://www.geeksforgeeks.org/centroid-decomposition-of-tree/
*/
#include <bits/stdc++.h>

#define ll long long
#define pb push_back
#define sz(x) (int)(x).size()
#define mp make_pair
#define f first
#define s second
#define all(x) x.begin(), x.end()

using namespace std;

const int N=3e5+5;
vector<vector<int> > graph(N),centroid_graph(N);
vector<int> visited(N),siz(N),local(N),what(N);
void dfs(int tr,int par)
{
    siz[tr]=1;
    for(auto p:graph[tr])
    {
        if(visited[p]||p==par)
            continue;
        dfs(p,tr);
        siz[tr]+=siz[p];
    }
}
int find_centroid(int tr,int n,int par)
{
    for(auto p:graph[tr])
    {
        if(p==par||visited[p])
            continue;
        if(siz[p]>n/2)
            return find_centroid(p,n,tr);
    }
    return tr;
}
int decompose(int tr)
{
    dfs(tr,-1);
    tr=find_centroid(tr,siz[tr],-1);
    visited[tr]=1;
    for(auto p:graph[tr])
    {
        if(visited[p])
            continue;
        int t=decompose(p);
        centroid_graph[t].pb(tr);
        centroid_graph[tr].pb(t);
    }
    return tr;
}
ll cnt=0;
vector<int> allowed(N),str,fin,start(N),finish(N);
void calculate(int tr,int par,int offset,int maxx,int minn)
{
    if(what[tr]==0){
        offset++;
        maxx=max(maxx,offset);
        if(offset==maxx)
        {
            str.pb(offset);
        }
    }
    else{
        offset--;
        minn=min(minn,offset);
        if(offset==minn)
        {
            fin.pb(-1*offset);
        }
    }
    for(auto p:graph[tr])
    {
        if(allowed[p]==0||p==par)
            continue;
        calculate(p,tr,offset,maxx,minn);
    }
}
void solve(int tr,int par)
{
    for(auto p:centroid_graph[tr])
    {
        if(p==par)
            continue;
        solve(p,tr);
    }
    int off;
    if(what[tr]==0)
        off=1;
    else
        off=-1;
    vector<int> s,f;
    for(auto p:graph[tr])
    {
        if(allowed[p]){
            calculate(p,tr,0,0,0);
            for(auto d:str)
            {
                if(off+d>=0)
                    cnt+=finish[d+off];
                s.pb(d);
            }
            for(auto d:fin)
            {
                if(d-off>=0)
                    cnt+=start[d-off];
                finish[d]++;
                f.pb(d);
            }
            for(auto d:str)
                start[d]++;
            str.clear();
            fin.clear();
        }
    }
    allowed[tr]=1;
    if(what[tr]==0)
        cnt+=finish[1];
    else
        cnt+=start[1];
    for(auto p:s)
        start[p]=0;
    for(auto p:f)
        finish[p]=0;
}
int main()
{
	int n;
	scanf("%i",&n);
	string s;
	cin >> s;
	for(int i=0;i<n;i++)
        what[i+1]=s[i]==')';
	for(int i=1;i<n;i++)
    {
        int a,b;
        scanf("%i %i",&a,&b);
        graph[a].pb(b);
        graph[b].pb(a);
    }
    int root=decompose(1);
    solve(root,-1);
    printf("%lld\n",cnt);
    return 0;
}

Compilation message

zagrade.cpp: In function 'int main()':
zagrade.cpp:134:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i",&n);
  ~~~~~^~~~~~~~~
zagrade.cpp:142:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%i %i",&a,&b);
         ~~~~~^~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 22648 KB Output is correct
2 Correct 24 ms 22776 KB Output is correct
3 Correct 23 ms 22976 KB Output is correct
4 Correct 23 ms 22976 KB Output is correct
5 Correct 22 ms 22976 KB Output is correct
6 Correct 25 ms 22976 KB Output is correct
7 Correct 24 ms 23056 KB Output is correct
8 Correct 23 ms 23056 KB Output is correct
9 Correct 23 ms 23056 KB Output is correct
10 Correct 22 ms 23056 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 466 ms 60840 KB Output is correct
2 Correct 473 ms 62980 KB Output is correct
3 Correct 478 ms 62980 KB Output is correct
4 Correct 483 ms 63236 KB Output is correct
5 Correct 445 ms 63236 KB Output is correct
6 Correct 488 ms 63236 KB Output is correct
7 Correct 479 ms 63236 KB Output is correct
8 Correct 443 ms 63236 KB Output is correct
9 Correct 447 ms 63236 KB Output is correct
10 Correct 443 ms 65084 KB Output is correct
11 Correct 442 ms 65084 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 22648 KB Output is correct
2 Correct 24 ms 22776 KB Output is correct
3 Correct 23 ms 22976 KB Output is correct
4 Correct 23 ms 22976 KB Output is correct
5 Correct 22 ms 22976 KB Output is correct
6 Correct 25 ms 22976 KB Output is correct
7 Correct 24 ms 23056 KB Output is correct
8 Correct 23 ms 23056 KB Output is correct
9 Correct 23 ms 23056 KB Output is correct
10 Correct 22 ms 23056 KB Output is correct
11 Correct 466 ms 60840 KB Output is correct
12 Correct 473 ms 62980 KB Output is correct
13 Correct 478 ms 62980 KB Output is correct
14 Correct 483 ms 63236 KB Output is correct
15 Correct 445 ms 63236 KB Output is correct
16 Correct 488 ms 63236 KB Output is correct
17 Correct 479 ms 63236 KB Output is correct
18 Correct 443 ms 63236 KB Output is correct
19 Correct 447 ms 63236 KB Output is correct
20 Correct 443 ms 65084 KB Output is correct
21 Correct 442 ms 65084 KB Output is correct
22 Correct 968 ms 65084 KB Output is correct
23 Correct 894 ms 65084 KB Output is correct
24 Correct 932 ms 65084 KB Output is correct
25 Correct 972 ms 65084 KB Output is correct
26 Correct 501 ms 65084 KB Output is correct
27 Correct 516 ms 65084 KB Output is correct
28 Correct 563 ms 65084 KB Output is correct
29 Correct 483 ms 65276 KB Output is correct
30 Correct 522 ms 65276 KB Output is correct
31 Correct 181 ms 65276 KB Output is correct
32 Correct 455 ms 65276 KB Output is correct