zcmimi's blog
查看原题

点击跳转

#include<bits/stdc++.h>
namespace ZDY{
    #pragma GCC optimize(3)
    #define il __inline__ __attribute__ ((always_inline))
    #define rg register
    #define ll long long
    #define ull unsigned long long
    #define db double
    #define sht short
    #define MB template <class T>il
    #define Fur(i,x,y) for(int i=x;i<=y;i++)
    #define Fdr(i,x,y) for(int i=x;i>=y;i--)
    #define fl(i,x) for(int i=head[x],to;to=e[i].to,i;i=e[i].nxt)
    #define clr(x,y) memset(x,y,sizeof(x))
    #define cpy(x,y) memcpy(x,y,sizeof(x))
    #define fin(s) freopen(s".in","r",stdin)
    #define fout(s) freopen(s".out","w",stdout)
    #define fcin ios::sync_with_stdio(false)
    #define l2(n) (int(log2(n)))
    #define inf 0x3f3f3f3f
    MB T ABS(T x){return x>0?x:-x;}
    MB T MAX(T x,T y){return x>y?x:y;}
    MB T MIN(T x,T y){return x<y?x:y;}
    MB T GCD(T x,T y){return y?GCD(y,x%y):x;}
    MB void SWAP(T &x,T &y){T t=x;x=y;y=t;}
}using namespace ZDY;using namespace std;
namespace IO{const char* ln="\n";const int str=1<<20;struct IN{char buf[str],*s,*t;bool _;IN():s(buf),t(buf),_(0){}il char gc(){return s==t&&((t=(s=buf)+fread(buf,1,str,stdin))==s)?EOF:(*s++);}IN&operator>>(char&ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)_=1;else ch=c;return *this;}IN& operator>>(char* ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;*ch=c;ch++;while((c=gc())!=EOF&&!isspace(c))*ch=c,ch++;if(c==EOF)_=1;return *this;}IN& operator>>(string& ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;ch+=c;while((c=gc())!=EOF&&!isspace(c))ch+=c;if(c==EOF)_=1;return *this;}template<typename T>IN&operator>>(T&x){if(_)return *this;char c=gc();bool ff=0;while(c!=EOF&&(c<'0'||c>'9'))ff^=(c=='-'),c=gc();if(c==EOF){_=1;return *this;}x=0;while(c!=EOF&&'0'<=c&&c<='9')x=(x<<3)+(x<<1)+c-48,c=gc();if(c==EOF)_=1;if(ff)x=-x;return *this;}}in;struct OUT{char buf[str],*s,*t;OUT():s(buf),t(buf+str){}~OUT(){fwrite(buf,1,s-buf,stdout);}void pt(char c){(s==t)?(fwrite(s=buf,1,str,stdout),*s++=c):(*s++=c);}OUT&operator<<(const char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(string s){for(int i=0;s[i];i++)pt(s[i]);return *this;}template<typename T>OUT&operator<<(T x){if(!x)return pt('0'),*this;if(x<0)pt('-'),x=-x;char a[30],t=0;while(x)a[t++]=x%10,x/=10;while(t--)pt(a[t]+'0');return *this;}}out;}using namespace IO;
#define N 100011
struct edge{
    int to,nxt,w;
}e[N*2];
int head[N],cnt=0,f[N][31],dis[N],d[N],n;
void add(int x,int y,int w){
    e[++cnt].to=y;e[cnt].w=w;e[cnt].nxt=head[x];head[x]=cnt;
}
void dfs(int x){
    for(int i=1;(1<<i)<=d[x];i++)
    if(f[x][i-1])f[x][i]=f[f[x][i-1]][i-1];
    fl(i,x)if(to!=f[x][0]){
        d[to]=d[x]+1;f[to][0]=x;
        dis[to]=dis[x]+e[i].w;
        dfs(to);
    }
}
int lca(int a,int b){
    if(d[a]<d[b])SWAP(a,b);
    Fdr(i,30,0)
        if(d[b]<=d[a]-(1<<i))a=f[a][i];
    if(a==b)return a;
    Fdr(i,30,0)
        if(f[a][i]!=f[b][i])a=f[a][i],b=f[b][i];
    return f[a][0];
}
int ask(int a,int b,int k){
    int tp=lca(a,b);
    if(d[a]-d[tp]+1>=k){
        int res=d[a]-k+1;
        Fdr(i,30,0)if((1<<i)<=d[a]-res)a=f[a][i];
        return a;
    }
    else{
        int res=d[tp]*2+k-d[a]-1;
        Fdr(i,30,0)
        if(d[b]-(1<<i)>=res)b=f[b][i];
        return b;
    }
}
int main(){
    fin("in");
    int T;
    in>>T;
    while(T--){
        clr(head,0);cnt=0;
        clr(f,0);
        clr(dis,0);
        clr(d,0);
        in>>n;
        int x,y,w;
        Fur(i,1,n-1)in>>x>>y>>w,add(x,y,w),add(y,x,w);
        dfs(1);
        char ch[20];
        while(1){
            in>>ch;if(ch[1]=='O')break;
            if(ch[0]=='D')in>>x>>y,out<<dis[x]+dis[y]-dis[lca(x,y)]*2<<ln;
            else in>>x>>y>>w,out<<ask(x,y,w)<<ln;
        }
    }
}
LG SP913 Query on a tree II
comment评论
Search
search