23333这个垃圾题之前扒过题解了2333
然而这一次做又错了。。。
直接暴力连边,然后缩一下点,重构变成DAG,然后DP。。
(然而在打tarjan的时候忘掉了inq[now]=0....而且把DP搞成了搜索2333)
(附:此题内存玄学)
1 #include<cstdio> 2 #include<iostream> 3 #include<algorithm> 4 #include<map> 5 #define N 1000005 6 #define LL long long 7 using namespace std; 8 inline int ra() 9 { 10 int x=0,f=1; char ch=getchar(); 11 while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();} 12 while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();} 13 return x*f; 14 } 15 struct in_data{ 16 int x,y,id,opt; 17 }a[N]; 18 struct edge{ 19 int to,next; 20 }e[N<<2],re[N]; 21 int head[N],rehead[N>>1],cnt,recnt,ind,top,n,x,y; 22 bool inq[N],vis[N>>1]; 23 map<LL , int > hh; 24 int ans; 25 int q[N],dfn[N],low[N]; 26 int size[N>>1],belong[N],tot; 27 bool cmp_x(in_data a, in_data b){ 28 return a.x<b.x; 29 } 30 bool cmp_y(in_data a, in_data b){ 31 return a.y<b.y; 32 } 33 void insert(int x, int y){ 34 e[++cnt].to=y; e[cnt].next=head[x]; head[x]=cnt; 35 } 36 void reinsert(int x, int y){ 37 re[++recnt].to=y; re[recnt].next=rehead[x]; rehead[x]=recnt; 38 } 39 void tarjan(int x) 40 { 41 q[++top]=x; dfn[x]=low[x]=++ind; 42 inq[x]=1; 43 for (int i=head[x];i;i=e[i].next) 44 if (!dfn[e[i].to]) 45 { 46 tarjan(e[i].to); 47 low[x]=min(low[x],low[e[i].to]); 48 } 49 else if (inq[e[i].to]) low[x]=min(low[x],dfn[e[i].to]); 50 int now=-1; 51 if (dfn[x]==low[x]) 52 { 53 tot++; 54 while (now!=x) 55 { 56 now=q[top--]; 57 belong[now]=tot; 58 size[tot]++; 59 inq[now]=0; //........ 60 } 61 } 62 } 63 void rebuild() 64 { 65 for (int x=1; x<=n; x++) 66 for (int i=head[x];i;i=e[i].next) 67 if (belong[x]!=belong[e[i].to]) 68 reinsert(belong[x],belong[e[i].to]); 69 } 70 void dfs(int x) 71 { 72 vis[x]=1; int mx=0; 73 for (int i=rehead[x];i;i=re[i].next) 74 { 75 if (!vis[re[i].to]) dfs(re[i].to); 76 mx=max(size[re[i].to],mx); 77 } 78 ans=max(ans,size[x]+=mx); 79 } 80 int main() 81 { 82 n=ra(); x=ra(); y=ra(); 83 for (int i=1; i<=n; i++) a[i].x=ra(),a[i].y=ra(),a[i].opt=ra(),hh[(LL)a[i].x*N+a[i].y]=i,a[i].id=i; 84 sort(a+1,a+n+1,cmp_x); 85 for (int i=1; i<=n; i++) 86 if (a[i].opt==1) 87 { 88 for (int j=i-1; j>=1; j--) 89 if (a[i].x==a[j].x) insert(a[i].id,a[j].id); 90 else break; 91 for (int j=i+1; j<=n; j++) 92 if (a[i].x==a[j].x) insert(a[i].id,a[j].id); 93 else break; 94 } 95 sort(a+1,a+n+1,cmp_y); 96 for (int i=1; i<=n; i++) 97 if (a[i].opt==2) 98 { 99 for (int j=i-1; j>=1; j--) 100 if (a[i].y==a[j].y) insert(a[i].id,a[j].id); 101 else break; 102 for (int j=i+1; j<=n; j++) 103 if (a[i].y==a[j].y) insert(a[i].id,a[j].id); 104 else break; 105 } 106 for (int i=1; i<=n; i++) 107 if (a[i].opt==3) 108 { 109 for (int j=a[i].x-1; j<=a[i].x+1; j++) 110 for (int k=a[i].y-1; k<=a[i].y+1; k++) 111 if (j!=a[i].x || k!=a[i].y) 112 if (hh[(LL)j*N+k]) insert(a[i].id,hh[(LL)j*N+k]); 113 } 114 for (int i=1; i<=n; i++) 115 if (!dfn[i]) tarjan(i); 116 rebuild(); 117 for (int i=1; i<=tot; i++) 118 if (!vis[i]) dfs(i); 119 printf("%d ",ans); 120 return 0; 121 }