Submission #414494

#	Time	Username	Problem	Language	Result	Execution time	Memory
414494		Ruxandra985	Joker (BOI20_joker)	C++14	14 / 100	2049 ms	14248 KiB

Joker

#include <bits/stdc++.h>
#define DIMN 400010
using namespace std;
int tt[DIMN];
int sz[DIMN] , opt[DIMN];
int n , m;
pair <int , int> mch[DIMN];
vector <pair <int , int> > s;
vector <int> v;


int idk = 76;

int root (int x){
    while (tt[x] != x)
        x = tt[x];
    return x;
}

void unite (int x, int y){
    int radx = root(x), rady = root(y);

    //printf ("add %d %d\n" , x , y);

    if (sz[radx] < sz[rady])
        swap (radx,rady);

    s.push_back(make_pair(radx,rady)); /// stiva pt undo
    sz[radx] += sz[rady];
    tt[rady] = radx;
}

void undo (){
    int x = s.back().first, y = s.back().second;
    s.pop_back();

    //printf ("undo\n");
    sz[x] -= sz[y];
    tt[y] = y;
}

void solve (int st , int dr , int l , int r){
    int mid = (st + dr)/2 , i , poz , x , y , m2;

    /*if (st == 77 && dr == 90){

        printf ("a");
    }

    if (st == 63 && dr == 64){

        printf ("%d %d %d %d\n" , st , dr , l , r);

        for (i = 0 ; i < v.size() ; i++){
            printf ("%d " , v[i]);
        }

        printf ("\n\n\n\n");
        printf ("a");
    }*/

    /*if (st <= 82 && 82 <= dr){

        printf ("%d %d %d %d\n" , st , dr , l , r);

        for (i = 0 ; i < v.size() ; i++){
            printf ("%d " , v[i]);
        }

        printf ("\n\n\n\n");



    }*/

    for (i = dr ; i >= mid ; i--){
        x = mch[i].first;
        y = mch[i].second;
        unite (x , y + n);
        unite (y , x + n);
        v.push_back(i);
    }

    l = max(l , 1);

    poz = 0;
    for (i = l ; i <= r && i < mid ; i++){

        x = mch[i].first;
        y = mch[i].second;

        if (root(x) == root(y) || root(y + n) == root(x + n)){
            break;
        }

        unite (x , y + n);

        unite (y , x + n);

        v.push_back(i);

        poz = i;

    }
    opt[mid] = poz;

    for (i = l ; i <= poz ; i++){
        undo();
        undo();
        v.pop_back();
    }

    if (st <= mid - 1)
        solve (st , mid - 1 , l , poz);

    for (i = mid ; i <= dr; i++){
        undo();
        undo();
        v.pop_back();
    }

    if (mid + 1 <= dr){
        m2 = (dr + mid + 1) / 2;

        for (i = l ; i < poz ; i++){
            x = mch[i].first;
            y = mch[i].second;
            unite (x , y + n);
            unite (y , x + n);
            v.push_back(i);

        }

        solve(mid + 1 , dr , poz , r);

        for (i = l ; i < poz ; i++){
            undo();
            undo();
            v.pop_back();
        }
    }

    /// convine sa te duci mai intai in dreapta, pastrezi tot ce ai adaugat
}

int main()
{
    FILE *fin = stdin;
    FILE *fout = stdout;
    int q , i , x , y , poz , j , l , r;
    fscanf (fin,"%d%d%d",&n,&m,&q);
    for (i = 1 ; i <= m ; i++){
        fscanf (fin,"%d%d",&mch[i].first,&mch[i].second);
    }

    /// opt se calculeaza intre 1 si M + 1

    for (i = 1 ; i <= 2 * n ; i++){
        tt[i] = i;
        sz[i] = 1;
    }

    /*/// ----------------------------------------------------------------------

    for (i = m ; i >= idk ; i--){

        x = mch[i].first;
        y = mch[i].second;

        if (root(x) == root(y) || root(y + n) == root(x + n)){
            break;
        }

        unite (x , y + n);

        unite (y , x + n);

    }

    for (i = 1 ; i < idk ; i++){

        x = mch[i].first;
        y = mch[i].second;

        if (root(x) == root(y) || root(y + n) == root(x + n)){
            break;
        }

        unite (x , y + n);

        unite (y , x + n);


    }

    printf ("%d\n" , i - 1);

    for (i = 1 ; i <= 2 * n ; i++){
        tt[i] = i;
        sz[i] = 1;
    }
    s.clear();

    /// ----------------------------------------------------------------------*/


    for (i = m ; i ; i--){

        x = mch[i].first;
        y = mch[i].second;

        if (root(x) == root(y) || root(y + n) == root(x + n)){
            break;
        }

        unite (x , y + n);

        unite (y , x + n);
    }
    poz = i + 1;
    for (j = i + 1 ; j <= m ; j++){
        undo();
        undo();
    }

    int where = poz;
    solve (poz , m , 1 , m); /// te asiguri ca dreapta nu cauzeaza ciclu impar
    //printf ("-----------------\n");

    for (i = 1 ; i <= m ; i++){
        x = mch[i].first;
        y = mch[i].second;

        if (root(x) == root(y) || root(y + n) == root(x + n)){
            break;
        }

        unite (x , y + n);

        unite (y , x + n);
    }

    poz = i - 1;
    opt[m + 1] = poz;
    for (j = i - 1 ; j ; j--){
        undo();
        undo();
    }

    for (;q;q--){
        fscanf (fin,"%d%d",&l,&r);
        if (opt[r + 1] >= l - 1 && r + 1 >= where)
            fprintf (fout,"NO\n");
        else fprintf (fout,"YES\n");
    }
    return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'void solve(int, int, int, int)':
Joker.cpp:43:47: warning: variable 'm2' set but not used [-Wunused-but-set-variable]
   43 |     int mid = (st + dr)/2 , i , poz , x , y , m2;
      |                                               ^~
Joker.cpp: In function 'int main()':
Joker.cpp:151:12: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  151 |     fscanf (fin,"%d%d%d",&n,&m,&q);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:153:16: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  153 |         fscanf (fin,"%d%d",&mch[i].first,&mch[i].second);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:251:16: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  251 |         fscanf (fin,"%d%d",&l,&r);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 0 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29