LCA y Minimum Cost Arborescence

Live Archive/2045 - Closest Common Ancestors.cpp

@@ -0,0 +1,88 @@
+#include <cstdio>
+#include <cstring>
+#include <algorithm>
+
+using namespace std;
+
+#define MAX_N 100000
+#define LOG2_MAXN 16
+
+// NOTA : memset(parent,-1,sizeof(parent));
+int N,parent[MAX_N],L[MAX_N];
+int P[MAX_N][LOG2_MAXN];
+
+int get_level(int u){
+    if(L[u]!=-1) return L[u];
+    else if(parent[u]==-1) return 0;
+    return 1+get_level(parent[u]);
+}
+
+void init(){
+	memset(L,-1,sizeof(L));
+	for(int i = 0;i<N;++i) L[i] = get_level(i);
+
+	memset(P,-1,sizeof(P));
+
+	for(int i = 0;i<N;++i) P[i][0] = parent[i];
+
+	for(int j = 1;(1<<j)<N;++j)
+	    for(int i = 0;i<N;++i)
+		    if(P[i][j-1]!=-1)
+			    P[i][j] = P[P[i][j-1]][j-1];
+}
+
+int LCA(int p, int q){
+    if(L[p]<L[q]) swap(p,q);
+
+    int log = 1;
+    while((1<<log)<=L[p]) ++log;
+    --log;
+
+    for(int i = log;i>=0;--i)
+        if(L[p]-(1<<i)>=L[q])
+            p = P[p][i];
+
+    if(p==q) return p;
+
+    for(int i = log;i>=0;--i){
+        if(P[p][i]!=-1 && P[p][i]!=P[q][i]){
+            p = P[p][i];
+            q = P[q][i];
+        }
+    }
+
+    return parent[p];
+}
+
+int main(){
+    int u,v,m,Q,ans[MAX_N];
+
+    while(scanf("%d",&N)==1){
+        memset(parent,-1,sizeof(parent));
+
+        for(int i = 0;i<N;++i){
+            scanf("%d:(%d)",&u,&m); --u;
+
+            for(int j = 0;j<m;++j){
+                scanf("%d",&v); --v;
+                parent[v] = u;
+            }
+        }
+
+        init();
+        memset(ans,0,sizeof(ans));
+        scanf("%d\n",&Q);
+
+        for(int q = 0;q<Q;++q){
+            scanf("%*[\r\n ]");
+            scanf("(%d %d)",&u,&v);
+            --u; --v;
+            ++ans[LCA(u,v)];
+        }
+
+        for(int i = 0;i<N;++i)
+            if(ans[i]!=0) printf("%d:%d\n",i+1,ans[i]);
+    }
+
+    return 0;
+}

PKU/3164 - Command Network.cpp

@@ -0,0 +1,143 @@
+#include <cstdio>
+#include <cstring>
+#include <cmath>
+#include <algorithm>
+
+using namespace std;
+
+#define MAX_V 100
+typedef double edge_cost;
+edge_cost INF = 1e10;
+
+int V,E,root,prev[MAX_V];
+bool adj[MAX_V][MAX_V];
+edge_cost G[MAX_V][MAX_V],MCA;
+bool visited[MAX_V],circle[MAX_V];
+
+void add_edge(int u, int v, edge_cost c){
+    if(adj[u][v]) G[u][v] = min(G[u][v],c);
+    else G[u][v] = c;
+    adj[u][v] = true;
+}
+
+void dfs(int v){
+    visited[v] = true;
+
+    for(int i = 0;i<V;++i)
+        if(!visited[i] && adj[v][i])
+            dfs(i);
+}
+
+bool check(){
+    memset(visited,false,sizeof(visited));
+    dfs(root);
+
+    for(int i = 0;i<V;++i)
+        if(!visited[i])
+            return false;
+
+    return true;
+}
+
+int exist_circle(){
+    prev[root] = root;
+
+    for(int i = 0;i<V;++i){
+        if(!circle[i] && i!=root){
+            prev[i] = i; G[i][i] = INF;
+
+            for(int j = 0;j<V;++j)
+                if(!circle[j] && adj[j][i] && G[j][i]<G[prev[i]][i])
+                    prev[i] = j;
+        }
+    }
+
+    for(int i = 0,j;i<V;++i){
+        if(circle[i]) continue;
+        memset(visited,false,sizeof(visited));
+
+        j = i;
+
+        while(!visited[j]){
+            visited[j] = true;
+            j = prev[j];
+        }
+
+        if(j==root) continue;
+        return j;
+    }
+
+    return -1;
+}
+
+void update(int v){
+    MCA += G[prev[v]][v];
+
+    for(int i = prev[v];i!=v;i = prev[i]){
+        MCA += G[prev[i]][i];
+        circle[i] = true;
+    }
+
+    for(int i = 0;i<V;++i)
+        if(!circle[i] && adj[i][v])
+            G[i][v] -= G[prev[v]][v];
+
+    for(int j = prev[v];j!=v;j = prev[j]){
+        for(int i = 0;i<V;++i){
+            if(circle[i]) continue;
+
+            if(adj[i][j]){
+                if(adj[i][v]) G[i][v] = min(G[i][v],G[i][j]-G[prev[j]][j]);
+                else G[i][v] = G[i][j]-G[prev[j]][j];
+                adj[i][v] = true;
+            }
+
+            if(adj[j][i]){
+                if(adj[v][i]) G[v][i] = min(G[v][i],G[j][i]);
+                else G[v][i] = G[j][i];
+                adj[v][i] = true;
+            }
+        }
+    }
+}
+
+bool min_cost_arborescence(int _root){
+    root = _root;
+    if(!check()) return false;
+
+    memset(circle,false,sizeof(circle));
+    MCA = 0;
+
+    int v;
+
+    while((v = exist_circle())!=-1)
+        update(v);
+
+    for(int i = 0;i<V;++i)
+        if(i!=root && !circle[i])
+            MCA += G[prev[i]][i];
+
+    return true;
+}
+
+int main(){
+    int M,a,b;
+    double x[100],y[100];
+
+    while(scanf("%d %d",&V,&M)==2){
+        for(int i = 0;i<V;++i) scanf("%lf %lf",&x[i],&y[i]);
+
+        memset(adj,false,sizeof(adj));
+
+        for(int i = 0;i<M;++i){
+            scanf("%d %d",&a,&b);
+            --a; --b;
+            add_edge(a,b,sqrt((x[a]-x[b])*(x[a]-x[b])+(y[a]-y[b])*(y[a]-y[b])));
+        }
+
+        if(!min_cost_arborescence(0)) printf("poor snoopy\n");
+        else printf("%.2lf\n",MCA);
+    }
+
+    return 0;
+}

TJU/1051 - Closest Common Ancestors.cpp

@@ -0,0 +1,88 @@
+#include <cstdio>
+#include <cstring>
+#include <algorithm>
+
+using namespace std;
+
+#define MAX_N 100000
+#define LOG2_MAXN 16
+
+// NOTA : memset(parent,-1,sizeof(parent));
+int N,parent[MAX_N],L[MAX_N];
+int P[MAX_N][LOG2_MAXN];
+
+int get_level(int u){
+    if(L[u]!=-1) return L[u];
+    else if(parent[u]==-1) return 0;
+    return 1+get_level(parent[u]);
+}
+
+void init(){
+	memset(L,-1,sizeof(L));
+	for(int i = 0;i<N;++i) L[i] = get_level(i);
+
+	memset(P,-1,sizeof(P));
+
+	for(int i = 0;i<N;++i) P[i][0] = parent[i];
+
+	for(int j = 1;(1<<j)<N;++j)
+	    for(int i = 0;i<N;++i)
+		    if(P[i][j-1]!=-1)
+			    P[i][j] = P[P[i][j-1]][j-1];
+}
+
+int LCA(int p, int q){
+    if(L[p]<L[q]) swap(p,q);
+
+    int log = 1;
+    while((1<<log)<=L[p]) ++log;
+    --log;
+
+    for(int i = log;i>=0;--i)
+        if(L[p]-(1<<i)>=L[q])
+            p = P[p][i];
+
+    if(p==q) return p;
+
+    for(int i = log;i>=0;--i){
+        if(P[p][i]!=-1 && P[p][i]!=P[q][i]){
+            p = P[p][i];
+            q = P[q][i];
+        }
+    }
+
+    return parent[p];
+}
+
+int main(){
+    int u,v,m,Q,ans[MAX_N];
+
+    while(scanf("%d",&N)==1){
+        memset(parent,-1,sizeof(parent));
+
+        for(int i = 0;i<N;++i){
+            scanf("%d:(%d)",&u,&m); --u;
+
+            for(int j = 0;j<m;++j){
+                scanf("%d",&v); --v;
+                parent[v] = u;
+            }
+        }
+
+        init();
+        memset(ans,0,sizeof(ans));
+        scanf("%d\n",&Q);
+
+        for(int q = 0;q<Q;++q){
+            scanf("%*[\r\n ]");
+            scanf("(%d%*[\r\n ,]%d)",&u,&v);
+            --u; --v;
+            ++ans[LCA(u,v)];
+        }
+
+        for(int i = 0;i<N;++i)
+            if(ans[i]!=0) printf("%d:%d\n",i+1,ans[i]);
+    }
+
+    return 0;
+}