POJ 3207 Ikki & #39; s Story IV, pojikki

POJ 3207 Ikki's Story IV, pojikki

Address: POJ 3207

Find the conflicting relationship. The two can only be one outside and the other can be one inside.

It can be used outside and inside to be 1 and 0, and finally judge whether there is a conflict between each pair.

The Code is as follows:

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;#define LL __int64const int INF=0x3f3f3f3f;int head[1100], cnt, top, ans, index;int dfn[1100], low[1100], instack[1100], stak[1100], belong[1100];struct node{    int u, v, next;}edge[1000000];struct N{    int l, r;}xian[10000];void add(int u, int v){    edge[cnt].v=v;    edge[cnt].next=head[u];    head[u]=cnt++;}int pan(N x, N y){    if((x.l>y.l&&x.l<y.r&&x.r>y.r)||(x.r>y.l&&x.r<y.r&&x.l<y.l))        return 1;    return 0;}void tarjan(int u){    dfn[u]=low[u]=++index;    instack[u]=1;    stak[++top]=u;    for(int i=head[u];i!=-1;i=edge[i].next)    {        int v=edge[i].v;        if(!dfn[v])        {            tarjan(v);            low[u]=min(low[u],low[v]);        }        else if(instack[v])        {            low[u]=min(dfn[v],low[u]);        }    }    if(dfn[u]==low[u])    {        ans++;        while(1)        {            int v=stak[top--];            instack[v]=0;            belong[v]=ans;            if(u==v) break;        }    }}void init(){    memset(head,-1,sizeof(head));    cnt=top=ans=index=0;    memset(dfn,0,sizeof(dfn));    memset(instack,0,sizeof(instack));}int main(){    int n, m, i, j;    scanf("%d%d",&n,&m);    init();    for(i=0;i<m;i++)    {        scanf("%d%d",&xian[i].l,&xian[i].r);        if(xian[i].l>xian[i].r) swap(xian[i].l,xian[i].r);    }    for(i=0;i<m;i++)    {        for(j=0;j<i;j++)        {            if(pan(xian[i],xian[j]))            {                add(i<<1,j<<1|1);                add(j<<1,i<<1|1);                add(i<<1|1,j<<1);                add(j<<1|1,i<<1);                //printf("%d %d\n%d %d\n",i<<1,j<<1|1,j<<1,i<<1|1);            }        }    }    for(i=0;i<2*m;i++)    {        if(!dfn[i])            tarjan(i);    }    int flag=0;    for(i=0;i<m;i++)    {        if(belong[i<<1]==belong[i<<1|1])        {            flag=1;            //printf("%d\n",i);            break;        }    }    if(flag) puts("the evil panda is lying again");    else        puts("panda is telling the truth...");    return 0;}