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#include<bits/stdc++.h> #define MAXN 30030 using namespace std; inline int rd(){ int x=0,y=1;char c=getchar(); while(c<'0' || c>'9'){if(c=='-')y=-y;c=getchar();} while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar(); return x*y; } int n,m; int son[MAXN][2],fa[MAXN],sz[MAXN],mx[MAXN],sum[MAXN],stk[MAXN],nxt[MAXN],val[MAXN]; bool rev[MAXN]; inline bool isroot(int x){ return son[fa[x]][0]!=x&&son[fa[x]][1]!=x; } inline bool is_right(int x){ return son[fa[x]][1]==x; } inline void pushup(int x){ mx[x]=sum[x]=val[x]; sz[x]=sz[son[x][0]]+sz[son[x][1]]+1; mx[x]=max(mx[x],max(mx[son[x][0]],mx[son[x][1]])); sum[x]+=sum[son[x][0]]+sum[son[x][1]]; } inline void pushdown(int x){ if(rev[x]){ rev[x]^=1,rev[son[x][0]]^=1,rev[son[x][1]]^=1; swap(son[x][0],son[x][1]); } } inline void Rotate(int x){ int f=fa[x],ff=fa[f],which=is_right(x); if(!isroot(f))son[ff][son[ff][1]==f]=x; son[f][which]=son[x][which^1]; fa[son[f][which]]=f;fa[f]=x; son[x][which^1]=f;fa[x]=ff; pushup(f);pushup(x); } inline void splay(int x){ int tot=0; stk[++tot]=x; for(int i=x; !isroot(i); i=fa[i])stk[++tot]=fa[i]; for(int i=tot; i>0; i--)pushdown(stk[i]); while(!isroot(x)){ int f=fa[x]; if(!isroot(f))Rotate((is_right(x)==is_right(f)?f:x)); Rotate(x); } } inline void access(int x){ int t=0; while(x){ splay(x); son[x][1]=t; pushup(x); t=x;x=fa[x]; } } inline void toroot(int x){ access(x);splay(x); rev[x]^=1; } inline void link(int x,int y){ toroot(x); fa[x]=y; splay(x); } inline void cut(int x,int y){ toroot(x);access(y);splay(y); son[y][0]=fa[x]=0; } inline int Find(int x){ access(x);splay(x); while(son[x][0])x=son[x][0]; return x; } map<int,int>mp[MAXN]; int main(){ n=rd(),m=rd(); for(int i=1; i<=n; i++){ val[i]=sum[i]=mx[i]=rd(); sz[i]=1; } char op[40]; while(m--){ scanf("%s",op); int x=rd(),y=rd(); if(op[0]=='U'){ access(x);splay(x); val[x]=y; pushup(x); } else if(op[0]=='L'){ if(Find(x)==Find(y))puts("NO"); else puts("YES"),link(x,y),mp[x][y]=mp[y][x]=1; } else if(op[0]=='C'){ if(mp[x][y])puts("YES"),cut(x,y),mp[x][y]=mp[y][x]=0; else puts("NO"); } else if(op[0]=='M'){ if(Find(x)!=Find(y))puts("-1"); else{ toroot(x);access(y);splay(y); printf("%d\n",mx[y]); } } else{ if(Find(x)!=Find(y))puts("-1"); else{ toroot(x);access(y);splay(y); printf("%d\n",sum[y]); } } } return 0; } |
