POJ3683 Falsita

http://poj.org/problem?id=3683

思路:2-SAT，输出任意一组方案，O(m+n)

#include<cstdio>
#include<iostream>
#include<cmath>
#include<cstring>
#include<algorithm>
int first[2000005],next[2000005],tot,go[2000005];
int First[2000005],Next[2000005],Tot,Go[2000005];
int b[200005],a[200005],n,ru[200005],low[200005],dfn[200005];
int op[2000005],belong[200005],instack[200005],vis[200005],st[200005],c[200005],col[200005],sz,num,top;
int read(){
    int t=0,f=1;char ch=getchar();
    while (ch<'0'||ch>'9'){if (ch=='-')f=-1;ch=getchar();}
    while ('0'<=ch&&ch<='9'){t=t*10+ch-'0';ch=getchar();}
    return t*f;
}
void insert(int x,int y){
    tot++;
    go[tot]=y;
    next[tot]=first[x];
    first[x]=tot;
}
void Insert(int x,int y){
    Tot++;
    Go[Tot]=y;
    Next[Tot]=First[x];
    First[x]=Tot;
}
bool jud(int x,int y){
    if (b[x]<=a[y]||a[x]>=b[y]) return 0;
    else return 1;
}
void build(){
    for (int i=1;i<=n;i++)
     for (int j=i+1;j<=n;j++){
        if (jud(i*2-1,j*2)){
            insert(i*2-1,j*2-1);
            insert(j*2,i*2);
        }
        if (jud(i*2-1,j*2-1)){
            insert(i*2-1,j*2);
            insert(j*2-1,i*2);
        }
        if (jud(i*2,j*2)){
            insert(i*2,j*2-1);
            insert(j*2,i*2-1);
        }
        if (jud(i*2,j*2-1)){
            insert(i*2,j*2);
            insert(j*2-1,i*2-1);
        }
     }
}
void init(){
    n=read();
    for (int i=1;i<=n;i++){
        a[i*2]=read();
        a[i*2]=a[i*2]*60+read();
        b[i*2-1]=read();
        b[i*2-1]=b[i*2-1]*60+read();
        int x=read();
        b[i*2]=a[i*2]+x;
        a[i*2-1]=b[i*2-1]-x;
    }
}
void tarjan(int x){
    low[x]=dfn[x]=++sz;
    instack[x]=vis[x]=1;st[++top]=x;
    for (int i=first[x];i;i=next[i]){
        int pur=go[i];
        if (!vis[pur]){
            tarjan(pur);
            low[x]=std::min(low[x],low[pur]);
        }else if (instack[pur]){
            low[x]=std::min(low[x],dfn[pur]);
        }
    }
    if (low[x]==dfn[x]){
        num++;
        while (st[top]!=x){
            instack[st[top]]=0;
            belong[st[top]]=num;
            top--;
        }
            instack[st[top]]=0;
            belong[st[top]]=num;
            top--;
    }
}
void Tarjan(){
    for (int i=1;i<=2*n;i++)
     if (!vis[i]) tarjan(i);
}
bool judge(){
    for (int i=1;i<=n;i++)
     if (belong[i*2]==belong[i*2-1]) {
            puts("NO");
            return 1;
     }
    puts("YES");
    return 0; 
}
void dfs(int x){
    if (col[x]) return ;col[x]=-1;
    for (int i=First[x];i;i=Next[i]){
        int pur=Go[i];
        dfs(pur);
    }
}
void topsort(){
    int t=0;
    for (int i=1;i<=num;i++)
     if (!ru[i]) c[++t]=i;
    while (t){
        int now=c[t--];
        if (col[now]) continue;col[now]=1;
        dfs(op[now]);
        for (int i=First[now];i;i=Next[i]){
            int pur=Go[i];
            ru[pur]--;
            if (ru[pur]==0) c[++t]=pur;
        }
    } 
}
void rebuild(){
    for (int i=1;i<=2*n;i++)
     for (int j=first[i];j;j=next[j]){
            int pur=go[j];
            if (belong[pur]==belong[i]) continue;
            ru[belong[i]]++;
            Insert(belong[pur],belong[i]);;
     }
    for (int i=1;i<=2*n;i++)
     op[belong[i*2]]=belong[i*2-1],op[belong[i*2-1]]=belong[i*2];
}
void print(int x){
    printf("%.2d:",x/60);
    printf("%.2d ",x%60);
}
void Output(){
    for (int i=1;i<=n;i++)
     if (col[belong[i*2]]==1){
            print(a[i*2]);print(b[i*2]);puts("");
     }else{
            print(a[i*2-1]);print(b[i*2-1]);puts("");    
     }
}
int main(){
    init();
    build();
    Tarjan();
    if (judge()) return 0;
    rebuild();
    topsort();
    Output();
}

为什么我会犯用错数组这种错误。。