Submission #647833

#	Time	Username	Problem	Language	Result	Execution time	Memory
647833		ToroTN	Flood (IOI07_flood)	C++14	10 / 100	2100 ms	13056 KiB

flood

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define X first
#define Y second
int n,m,x[100005],y[100005],wall1,wall2,a1,b1,a2,b2,go[100005][4],st,d[100005];
int nxt[100005][4],p[100005],rev[100005],num,dir,val;
//right=0 down=1 left 2 up=3
vector<pair<pair<int,int>,int > > v;
vector<int> g;
set<int> s;
void dfs(int u)
{
    for(int i=0;i<4;i++)
    {
        int way=(dir+2+i)%4;
        if(go[u][way]!=0&&go[u][way]!=p[u])
        {
            int bug=d[go[u][way]];
            if(bug!=1)
            {
                if(bug==-1)
                {
                    d[go[u][way]]=0;
                    g.pb(go[u][way]);
                    p[go[u][way]]=u;
                    dir=way;
                    rev[go[u][way]]=nxt[u][way];
                    dfs(go[u][way]);
                    if(val==-1)return;
                }else
                {
                    for(int j=0;j<(int)g.size();j++)
                    {
                        d[g[j]]=1;
                    }
                    s.erase(nxt[u][way]);
                    num=u;
                    while(1)
                    {
                        if(num==go[u][way])break;
                        s.erase(rev[num]);
                        num=p[num];
                    }
                    g.clear();
                    val=-1;
                    if(val==-1)return;
                }
            }
        }
    }
    val=-1;
    return;
}
int main()
{
    memset(d,-1,sizeof d);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d%d",&x[i],&y[i]);
        v.pb({{x[i],y[i]},i});
    }
    scanf("%d",&m);
    for(int i=1;i<=m;i++)
    {
        s.insert(i);
        scanf("%d%d",&wall1,&wall2);
        a1=x[wall1];
        b1=y[wall1];
        a2=x[wall2];
        b2=y[wall2];
        if(a1>a2)
        {
            swap(a1,a2);
            swap(wall1,wall2);
        }
        if(a1<a2)
        {
            go[wall1][1]=wall2;
            go[wall2][3]=wall1;
            nxt[wall1][1]=i;
            nxt[wall2][3]=i;
        }
        if(b1>b2)
        {
            swap(b1,b2);
            swap(wall1,wall2);
        }
        if(b1<b2)
        {
            go[wall1][0]=wall2;
            go[wall2][2]=wall1;
            nxt[wall1][0]=i;
            nxt[wall2][2]=i;
        }
    }
    sort(v.begin(),v.end());
    for(int i=0;i<(int)v.size();i++)
    {
        st=v[i].Y;
        if(d[st]==-1)
        {
            val=0;
            d[st]=0;
            dir=2;
            g.pb(st);
            dfs(st);
        }
    }
    printf("%d\n",(int)s.size());
    for(auto it:s)printf("%d\n",it);
}

Compilation message (stderr)

flood.cpp: In function 'int main()':
flood.cpp:58:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
flood.cpp:61:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         scanf("%d%d",&x[i],&y[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~
flood.cpp:64:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     scanf("%d",&m);
      |     ~~~~~^~~~~~~~~
flood.cpp:68:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         scanf("%d%d",&wall1,&wall2);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 3
• Subtask 5: 0 / 10
• Subtask 6: 0 / 3
• Subtask 7: 0 / 3
• Subtask 8: 0 / 3
• Subtask 9: 0 / 3
• Subtask 10: 0 / 9
• Subtask 11: 0 / 9
• Subtask 12: 0 / 9
• Subtask 13: 0 / 9
• Subtask 14: 0 / 9