LCA
题意：询问LCA，不过图不连通，如果两点不连通输出那串英文否则输出两点间的距离，模板题
#include#include #include using namespace std;#define N 10010#define M 10010#define Q 1000010int head[N];struct edge{ int u,v,w,next;}e[2*M];int __head[N];struct ask{ int u,v,lca,next;}ea[2*Q];int dir[N],fa[N],vis[N];inline void add_edge(int u ,int v ,int w ,int &k){ e[k].u = u; e[k].v = v; e[k].w = w; e[k].next = head[u]; head[u] = k++;}inline void add_ask(int u ,int v ,int &k){ ea[k].u = u; ea[k].v = v; ea[k].lca = -1; ea[k].next = __head[u]; __head[u] = k++;}int find(int x){ return x == fa[x] ? x : fa[x] = find(fa[x]);}void Tarjan(int u ,int c){ vis[u] = c; fa[u] = u; for(int k=head[u]; k!=-1; k=e[k].next) if(!vis[e[k].v]) { int v = e[k].v , w = e[k].w; dir[v] = dir[u] + w; Tarjan(v,c); fa[v] = u; } for(int k=__head[u]; k!=-1; k=ea[k].next) if(vis[ea[k].v] == c) ea[k].lca = ea[k^1].lca = find(ea[k].v);}int main(){ int n,m,q,k; while(scanf("%d%d%d",&n,&m,&q)!=EOF) { memset(head,-1,sizeof(head)); memset(__head,-1,sizeof(__head)); memset(vis,0,sizeof(vis)); k = 0; for(int i=0; i