LCA模板

来源：互联网发布：linux 流媒体服务器编辑：程序博客网时间：2024/06/14 08:06

tarjan：

#define up(i, j, k) for(int i = j; i <= k; ++i)#define down(i, j, k) for(int i = j; i >= k; --i)#include <cstdio>#include <cstdlib>#include <iostream>#include <cmath>#include <algorithm>#include <climits>#include <cstring>#include <string>#include <map>using namespace std;int aim[20000],len[20000],nxt[20000],first[10001];int _src[2000001],_aim[2000001],_lca[1000001],_nxt[2000001],_first[10001];int fa[10001],visit[10001],dist[10001];int tot,n,m,c;void addedge(int u,int v,int w){    aim[tot]=v; len[tot]=w; nxt[tot]=first[u]; first[u]=tot++;}void addask(int u,int v){    _src[tot]=u; _aim[tot]=v; _nxt[tot]=_first[u]; _first[u]=tot++;}int find(int v){    return fa[v]==v?v:fa[v]=find(fa[v]);}void tarjan(int u,int x){    visit[u]=x;    fa[u]=u;    for (int i=first[u];~i;i=nxt[i])        if (!visit[aim[i]])        {            dist[aim[i]]=dist[u]+len[i];            tarjan(aim[i],x);            fa[aim[i]]=u;        }    for (int i=_first[u];~i;i=_nxt[i])        if (visit[_aim[i]]==x)            _lca[i/2]=find(_aim[i]);}void init(){    memset(first,-1,sizeof(first));    memset(_first,-1,sizeof(_first));    memset(visit,0,sizeof(visit));}int main(){    while(scanf("%d%d%d",&n,&m,&c)!=EOF)    {        init();        tot=0;        up(i,1,m)        {            int u,v,w;            scanf("%d%d%d",&u,&v,&w);            addedge(u,v,w); addedge(v,u,w);        }        tot=0;        up(i,0,c-1)        {            int u,v;            scanf("%d%d",&u,&v);            addask(u,v); addask(v,u);            _lca[i]=-1;        }        tot=0;        up(i,1,n)            if (!visit[i])            {                dist[i]=0;                tarjan(i,++tot);            }        up(i,0,c-1)            if (~_lca[i]) printf("%d\n",dist[_src[i*2]]+dist[_aim[i*2]]-2*dist[_lca[i]]);            else printf("Not connected\n");    }}

rmq：

#define up(i, j, k) for(int i = j; i <= k; ++i)#define down(i, j, k) for(int i = j; i >= k; --i)#include <cstdio>#include <cstdlib>#include <iostream>#include <cmath>#include <algorithm>#include <climits>#include <cstring>#include <string>#include <map>using namespace std;int tot;int aim[80010],len[80010],nxt[80010],first[40010];int visit[40010],seq[80010],deep[80010],seqfirst[40010],dist[40010];int dp[80010][18];void addedge(int u,int v,int w){    aim[tot]=v; len[tot]=w; nxt[tot]=first[u]; first[u]=tot++;}void dfs(int u,int dep){    visit[u]=1; seq[++tot]=u; deep[tot]=dep; seqfirst[u]=tot;    for(int i=first[u];~i;i=nxt[i])    {        if (!visit[aim[i]])        {            dist[aim[i]]=dist[u]+len[i];            dfs(aim[i],dep+1);            seq[++tot]=u; deep[tot]=dep;        }    }}void st(int n){    up(i,1,n) dp[i][0]=i;    for(int j=1;(1<<j)<=n;++j)    {        for(int i=1;i+(1<<j)-1<=n;++i)        {            int a=dp[i][j-1], b=dp[i+(1<<(j-1))][j-1];            dp[i][j]=deep[a]<deep[b]?a:b;        }    }}int rmq(int l,int r){    int k=log2(r-l+1);    int a=dp[l][k],b=dp[r-(1<<k)+1][k];    return deep[a]<deep[b]?a:b;}int lca(int u,int v){    int l=seqfirst[u], r=seqfirst[v];    if (l>r) swap(l,r);    return seq[rmq(l,r)];}void init(){    memset(first,-1,sizeof(first));    memset(visit,0,sizeof(visit));    memset(seqfirst,0,sizeof(seqfirst));    dist[1]=0;}int main(){    int t;    scanf("%d",&t);    while (t--)    {        init();        int n,m;        scanf("%d%d",&n,&m);        tot=0;        up(i,1,n-1)        {            int u,v,w;            scanf("%d%d%d",&u,&v,&w);            addedge(u,v,w); addedge(v,u,w);        }        tot=0;        dfs(1,1);        st(2*n-1);        up(i,1,m)        {            int u,v;            scanf("%d%d",&u,&v);            printf("%d\n",dist[u]+dist[v]-2*dist[lca(u,v)]);        }    }}

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