对于一张无向图，需要你支持加边，删边，求路径疑惑和，修改权值四个操作
真丶LCT裸题
#include <cstdio>#define N 300010int n,m,op,x,y,tp;int v[N],w[N],f[N],ch[N][2],rev[N],sta[N];inline void reaD(int &x){ char Ch=getchar();x=0; for(;Ch>'9'||Ch<'0';Ch=getchar()); for(;Ch>='0'&&Ch<='9';x=x*10+Ch-'0',Ch=getchar());}inline int isr(int x){return ch[f[x]][0]!=x&&ch[f[x]][1]!=x;}inline int isl(int x){return ch[f[x]][1]==x;}inline void upd(int x){ if(!x) return; v[x]=w[x]; if(ch[x][0]) v[x]^=v[ch[x][0]]; if(ch[x][1]) v[x]^=v[ch[x][1]];}inline void swap(int &x,int &y){int z=x;x=y;y=z;}inline void pushdown(int x){ if(!(x&&rev[x])) return ; swap(ch[x][0],ch[x][1]); if(ch[x][1]) rev[ch[x][1]]^=1; if(ch[x][0]) rev[ch[x][0]]^=1; rev[x]=0;}inline void rot(int x){ int y=f[x],z=f[y],lor=isl(x); if(!isr(y))ch[z][ch[z][1]==y]=x;f[x]=z; ch[y][lor]=ch[x][lor^1]; if(ch[y][lor]) f[ch[y][lor]]=y; ch[x][lor^1]=y;f[y]=x; upd(y);upd(x);}inline void splay(int x){ sta[tp=1]=x; for(int i=x;!isr(i);i=f[i]) sta[++tp]=f[i]; for(;tp;tp--) pushdown(sta[tp]); for(;!isr(x);rot(x))if(!isr(f[x]))rot(isl(f[x])^isl(x)?x:f[x]);}inline void access(int x){int t=0;for(;x;t=x,x=f[x]) splay(x),ch[x][1]=t,upd(x);}inline void reverse(int x){access(x);splay(x);rev[x]^=1;}inline int fifa(int x){access(x);splay(x);while(ch[x][0])x=ch[x][0];return x;}inline int query(int x,int y){reverse(x);access(y);splay(y);return v[y];}inline void link(int x,int y){reverse(x);f[x]=y;splay(x);}inline void cut(int x,int y){reverse(x);access(y);splay(y);ch[y][0]=f[x]=0;}inline void change(int x,int y){access(x);splay(x);w[x]=y;upd(x);}int main(){ reaD(n);reaD(m); for(int i=1;i<=n;i++) reaD(w[i]); for(int i=1;i<=m;i++){ reaD(op);reaD(x);reaD(y); if(op==0) PRintf("%d/n",query(x,y)); else if(op==1) if(fifa(x)!=fifa(y)) link(x,y);else; else if(op==2) if(fifa(x)==fifa(y)) cut(x,y); else; else change(x,y); }}新闻热点
疑难解答
