hdu5877 Weak Pair 【树状数组+dfs】

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#pragma comment(linker, "/STACK:1024000000,1024000000")#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <string>#include <cmath>#include <stdlib.h>#include <time.h>using namespace std;const int N=2e5+10;typedef long long ll;ll ans,k,a[N],w[N],b[N];int n,in[N],c[N];vector<int>g[N];int get(int x){    int ret=0;    //if(x>n) x=2*n;    while(x>0)    {        ret+=c[x];        x-=x&-x;    }    return ret;}void add(int x,int val){    while(x<=2*n)    {        c[x]+=val;        x+=x&-x;    }}void dfs(int x){    ans+=get(w[x]);    add(a[x],1);    for(int i=0;i<g[x].size();i++)    {        int y=g[x][i];        dfs(y);    }    add(a[x],-1);}int main(){    int _,u,v;    scanf("%d",&_);    while(_--)    {        scanf("%d%lld",&n,&k);        for(int i=1;i<=n;i++)            g[i].clear();        for(int i=1;i<=n;i++)        {            scanf("%lld",&a[i]);            if(a[i]==0) w[i]=1e18;            else w[i]=k/a[i];            b[2*i-2]=a[i];            b[2*i-1]=w[i];        }        sort(b,b+2*n);        for(int i=1;i<=n;i++)        {            a[i]=lower_bound(b,b+2*n,a[i])-b+1;            w[i]=lower_bound(b,b+2*n,w[i])-b+1;        }        memset(in,0,sizeof(in));        memset(c,0,sizeof(c));        for(int i=1;i<n;i++)        {            scanf("%d%d",&u,&v);            g[u].push_back(v);            in[v]++;        }        int rt;        for(int i=1;i<=n;i++)        {            if(!in[i])            {                rt=i;                break;            }        }        ans=0;        dfs(rt);        printf("%lld\n",ans);    }    return 0;}/*#pragma comment(linker, "/STACK:1024000000,1024000000")#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <string>#include <cmath>#include <stdlib.h>#include <time.h>using namespace std;const int N=2e5+10;typedef long long ll;ll ans,k,a[N],b[N];int n,in[N],c[N];vector<int>g[N];int get(int x){    int ret=0;    while(x>0)    {        ret+=c[x];        x-=x&-x;    }    return ret;}void add(int x,int val){    while(x<=2*n)    {        c[x]+=val;        x+=x&-x;    }}void dfs(int x){    ll v;    if(b[a[x]-1]==0) v=n+5;    else    {        v=k/b[a[x]-1];        v=lower_bound(b,b+n,v)-b+1;    }    //printf("%d %d %d %d\n",v,x,get(n),get(v+1));    ans+=get(v);    add(a[x],1);    for(int i=0;i<g[x].size();i++)    {        int y=g[x][i];        dfs(y);    }    add(a[x],-1);}int main(){    int _,u,v;    scanf("%d",&_);    while(_--)    {        scanf("%d%lld",&n,&k);        for(int i=1;i<=n;i++)        {            scanf("%lld",&a[i]);            b[i-1]=a[i];        }        for(int i=1;i<=n;i++)        {            g[i].clear();        }        sort(b,b+n);        for(int i=1;i<=n;i++)        {            a[i]=lower_bound(b,b+n,a[i])-b+1;        }        memset(in,0,sizeof(in));        memset(c,0,sizeof(c));        for(int i=1;i<n;i++)        {            scanf("%d%d",&u,&v);            g[u].push_back(v);            in[v]++;        }        int rt;        for(int i=1;i<=n;i++)        {            if(!in[i])            {                rt=i;                break;            }        }        ans=0;        dfs(rt);        printf("%lld\n",ans);    }    return 0;}*/
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