poj 3683 Priest John's Busiest Day 2-sat

来源：互联网发布：linux 命令选项是什么编辑：程序博客网时间：2024/05/18 02:52
#include<cstdio>#include<algorithm>#include<vector>#include<cstring>#include<stack>using namespace std;const int maxn = 2000 + 30;vector<int> G[maxn], G2[maxn];vector<int> S;int vis[maxn], sccno[maxn], scc_cnt;int n,m;int s[maxn],t[maxn],d[maxn];void dfs1(int u){    if(vis[u]) return;    vis[u] = 1;    for(int i = 0; i < G[u].size(); i++) dfs1(G[u][i]);    S.push_back(u);}void dfs2(int u){    if(sccno[u]) return;    sccno[u] = scc_cnt;    for(int i = 0; i < G2[u].size(); i++) dfs2(G2[u][i]);}void find_scc(int n){    int i;    scc_cnt = 0;    S.clear();    memset(sccno, 0, sizeof(sccno));    memset(vis, 0, sizeof(vis));    for(i = 0; i < n; i++) dfs1(i);    for(i = n-1; i >= 0; i--)    if(!sccno[S[i]]) { scc_cnt++; dfs2(S[i]); }}int main(){    while(scanf("%d",&n)!=EOF)    {        int i,j;        int x,y;        for(i=0;i<2*n;i++)        {            G[i].clear();            G2[i].clear();        }        for(i=0;i<n;i++)        {            scanf("%d:%d",&x,&y);            s[i]=x*60+y;            scanf("%d:%d",&x,&y);            t[i]=x*60+y;            scanf("%d",&d[i]);        }        for(i=0;i<n;i++)            for(j=i+1;j<n;j++)            {                if( !( s[j]>=s[i]+d[i] || s[j]+d[j]<=s[i] ) )                {                    G[i].push_back(j+n); G2[j+n].push_back(i);                    G[j].push_back(i+n); G2[i+n].push_back(j);                }                if( !( t[j]-d[j]>=s[i]+d[i] || t[j]<=s[i] ) )                {                    G[i].push_back(j); G2[j].push_back(i);                    G[j+n].push_back(i+n); G2[i+n].push_back(j+n);                }                if( !( t[j]-d[j]>=t[i] || t[j]<=t[i]-d[i] ) )                {                    G[i+n].push_back(j); G2[j].push_back(i+n);                    G[j+n].push_back(i); G2[i].push_back(j+n);                }                if( !( t[i]-d[i]>=s[j]+d[j] || t[i]<=s[j] ) )                {                    G[i+n].push_back(j+n); G2[j+n].push_back(i+n);                    G[j].push_back(i); G2[i].push_back(j);                }            }        find_scc(2*n);        int flag=1;        for(i=0;i<n;i++)        {            if(sccno[i]==sccno[i+n])            {                printf("NO\n");                flag=0;                break;            }        }        if(flag)        {            printf("YES\n");            for(i=0;i<n;i++)            {                if(sccno[i]>sccno[i+n])                    printf("%02d:%02d %02d:%02d\n",s[i]/60,s[i]%60,(s[i]+d[i])/60,(s[i]+d[i])%60);                else printf("%02d:%02d %02d:%02d\n",(t[i]-d[i])/60,(t[i]-d[i])%60,t[i]/60,t[i]%60);            }        }    }    return 0;}
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