oj.uz

답안 #170247

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
170247 2019-12-24T11:06:11 Z Ruxandra985 Mousetrap (CEOI17_mousetrap) C++14
45 / 100
 988 ms 68600 KB 
#include <cstdio>
#include <vector>
#include <iostream>
#include <queue>
#define DIMN 1000010
using namespace std;
int fth[DIMN] , w[DIMN] , maxi[DIMN] , t , blocked[DIMN] , niv[DIMN];
int aib[DIMN];
pair <int,int> aint[4*DIMN];
vector <int> v[DIMN];
priority_queue <pair <pair <int,int>,int> > h;
FILE *fin = stdin;
FILE *fout = stdout;
inline void lazy_update (int nod,int st,int dr){
    if (!aint[nod].second) /// nu ii trb lazy
        return;
    if (st<dr){ /// nu e frunza
        aint[2*nod].second+=aint[nod].second; /// pass lazy
        aint[2*nod+1].second+=aint[nod].second;
    }
    aint[nod].first+=aint[nod].second;
    aint[nod].second=0;
}

int query (int nod , int st ,int dr , int poz){
    int mid = ( st + dr )/2 , x;
    lazy_update(nod , st , dr);
    if (st == dr)
        return aint[nod].first;

    if (poz<=mid)
        x = query (2*nod,st,mid,poz);
    else
        x = query (2*nod+1,mid+1,dr,poz);
    lazy_update (2*nod,st,mid);
    lazy_update (2*nod+1,mid+1,dr);
    return x;

}
void update_interv (int nod,int st,int dr,int l,int r,int add){
    int mid=(st+dr)/2;
    lazy_update (nod,st,dr);
    if (l<=st && dr<=r){
        aint[nod].second+=add; /// nu ma mai duc in jos
        lazy_update (nod,st,dr);
        return;
    }
    if (l<=mid)
        update_interv (2*nod,st,mid,l,r,add);
    if (mid+1<=r)
        update_interv (2*nod+1,mid+1,dr,l,r,add);
    lazy_update (2*nod,st,mid);
    lazy_update (2*nod+1,mid+1,dr);
}
void dfs (int nod,int tt){
    int i , vecin , maxii = 0 , poz;
    fth[nod] = tt;
    for (i=0;i<v[nod].size();i++){
        vecin = v[nod][i];
        if (vecin != tt){
            niv[vecin] = 1 + niv[nod];
            dfs (vecin , nod);
            /// cat de in jos te poti duce din nod
        }
    }
   // if (nod == 5)
     //   printf ("a");
    /// maxi[nod] = nr de mutari ale soarecelui ca sa se plimbe in subarborele nod
    /// iar apoi sa revina in nod
    poz = -1;
    maxii = -1;
    for (i=0;i<v[nod].size();i++){
        vecin = v[nod][i];
        if (vecin != tt){
            if (maxii < maxi[vecin]){
                maxii = maxi[vecin];
                poz = vecin;
            }
        }
    }
    maxi[nod] = -1;
    int x = v[nod].size();
    for (i=0;i<v[nod].size();i++){
        vecin = v[nod][i];
        if (vecin != tt && vecin != poz){
            maxi[nod] = max (maxi[nod] , maxi[vecin] + 1 + 1 + x - 3);
            /// 1 ca sa cureti drumul vecin , nod dupa ce se blocheaza
            /// 1 ca sa blochezi cel mai nasol pasaj
        }
    }
    if (poz != -1){
        if (maxi[nod] == -1)
            maxi[nod] = maxi[poz] + 1 + x - 2;
        maxi[nod] = min(maxi[nod] , maxi[poz] + 1 + x - 2);
    }
    else maxi[nod] = 0;
    /// pot sa aleg sa nu blochez cel mai nasol pasaj
    if (v[nod].size() == 2){
       // printf ("%d %d\n",nod,maxi[nod]);
        maxi[nod] = 1;
    }
}
int main()
{
    int n , m , i , x , y , nod , elem , mustblock , poz , sp ,sol , can , tt;
    int vecin;
    fscanf (fin,"%d%d%d",&n,&t,&m);
    for (i=1;i<n;i++){
        fscanf (fin,"%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    v[m].push_back(0);
    dfs (m , 0);
    /// practic soarecele isi alege un singur subarbore in care se duce cat vrea el
    /// apio cand se blocheaza
    nod = t;
    elem = 0;
    w[++elem] = t;
    while (fth[nod]){
        w[++elem] = fth[nod];
        nod = fth[nod];
    }
    mustblock = 0;
    for (i=1;i<=elem;i++){
        if (w[i] == t)
            continue;
        mustblock += v[w[i]].size() - 2; /// nici tatal
    }
    sol = 0;
    nod = m;
    can = 0;
    tt = 0;
    poz = elem;
    while (nod != t){
        //printf ("%d ", nod);
        for (i=0;i<v[nod].size();i++){
            vecin = v[nod][i];
            if (vecin != tt && vecin != w[poz-1]){
                h.push(make_pair(make_pair(maxi[vecin] , -niv[vecin]) , vecin));
                /// astia sunt vecinii pe care poti tu sa ii blochezi
            }
        }

        tt = nod;
        nod = w[poz-1];
        poz--;
    }
    can = niv[t];
    for (i=1;i<=niv[t];i++)
        update_interv (1 , 1 , n , i , i , i);
    /// o sa tin niv de la 1
    int nr = 0;
    while (can && !h.empty()){
        nod = h.top().second;
        h.pop();
        while (!h.empty() && !query(1 ,1 , n , niv[nod])){ /// poti
            nod = h.top().second;
            h.pop();
        }
        if (!query(1 ,1 , n , niv[nod]))
            break;
        update_interv (1 , 1 , n , niv[nod] , n , -1);
        blocked[nod] = 1;
        nr++;
        can--;
    }
    nod = m;
    tt = 0;
    int tos = 0;
    /// poti sa blochezi can pasaje in drumul
    while (nod != t){
        sp = 0;
        tos = 0;
        for (i=0;i<v[nod].size();i++){
            vecin = v[nod][i];
            if (vecin != tt && !blocked[vecin] && vecin != w[elem-1]){
                sp = max (sp , maxi[vecin] + 1 + 1 + mustblock - nr - 1 - 1);
                tos++;
                /// 1 ca sa cureti drumul vecin , nod dupa ce se blocheaza
                /// 1 ca sa blochezi cel mai nasol pasaj
            }
        }
        sol = max (sol , sp);
        tt = nod;
        mustblock -= tos;
        nod = w[elem-1];
        elem--;
    }
    fprintf (fout,"%d",sol + nr);
    return 0;
}

Compilation message

mousetrap.cpp: In function 'void dfs(int, int)':
mousetrap.cpp:58:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i=0;i<v[nod].size();i++){
              ~^~~~~~~~~~~~~~
mousetrap.cpp:72:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i=0;i<v[nod].size();i++){
              ~^~~~~~~~~~~~~~
mousetrap.cpp:83:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i=0;i<v[nod].size();i++){
              ~^~~~~~~~~~~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:137:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i=0;i<v[nod].size();i++){
                  ~^~~~~~~~~~~~~~
mousetrap.cpp:175:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i=0;i<v[nod].size();i++){
                  ~^~~~~~~~~~~~~~
mousetrap.cpp:107:12: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fscanf (fin,"%d%d%d",&n,&t,&m);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:109:16: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         fscanf (fin,"%d%d",&x,&y);
         ~~~~~~~^~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 23 ms 23824 KB Output is correct
4 Correct 23 ms 23804 KB Output is correct
5 Correct 23 ms 23928 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 24 ms 23804 KB Output is correct
9 Correct 24 ms 23928 KB Output is correct
10 Correct 23 ms 23928 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 440 ms 66856 KB Output is correct
2 Correct 401 ms 62752 KB Output is correct
3 Correct 988 ms 68600 KB Output is correct
4 Correct 448 ms 46264 KB Output is correct
5 Correct 971 ms 68300 KB Output is correct
6 Correct 975 ms 68280 KB Output is correct

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 23 ms 23824 KB Output is correct
4 Correct 23 ms 23804 KB Output is correct
5 Correct 23 ms 23928 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 24 ms 23804 KB Output is correct
9 Correct 24 ms 23928 KB Output is correct
10 Correct 23 ms 23928 KB Output is correct
11 Correct 23 ms 23800 KB Output is correct
12 Correct 24 ms 23928 KB Output is correct
13 Correct 23 ms 23928 KB Output is correct
14 Correct 24 ms 23924 KB Output is correct
15 Correct 24 ms 23928 KB Output is correct
16 Incorrect 24 ms 23928 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 23 ms 23824 KB Output is correct
4 Correct 23 ms 23804 KB Output is correct
5 Correct 23 ms 23928 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 24 ms 23804 KB Output is correct
9 Correct 24 ms 23928 KB Output is correct
10 Correct 23 ms 23928 KB Output is correct
11 Correct 440 ms 66856 KB Output is correct
12 Correct 401 ms 62752 KB Output is correct
13 Correct 988 ms 68600 KB Output is correct
14 Correct 448 ms 46264 KB Output is correct
15 Correct 971 ms 68300 KB Output is correct
16 Correct 975 ms 68280 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 24 ms 23928 KB Output is correct
19 Correct 23 ms 23928 KB Output is correct
20 Correct 24 ms 23924 KB Output is correct
21 Correct 24 ms 23928 KB Output is correct
22 Incorrect 24 ms 23928 KB Output isn't correct
23 Halted 0 ms 0 KB -