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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#621362#5439. Meet in the MiddlekaiyiRE 11ms98296kbC++144.4kb2024-10-08 13:48:212024-10-08 13:48:23

Judging History

你现在查看的是最新测评结果

  • [2024-10-08 13:48:23]
  • 评测
  • 测评结果:RE
  • 用时:11ms
  • 内存:98296kb
  • [2024-10-08 13:48:21]
  • 提交

answer

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N = 1e6+10;
int n,q;
vector<pair<int,int> >A[N];
vector<pair<int,int> >B[N];
vector<pair<int,int> >b[N];
int ans[N*5];

int A_dfn[N],B_dfn[N];
int dfn;
int e[N<<1],tot;
int ST[N<<1][30];
int p[N];
int rdis[N];//B 树到根的距离
int a[N],to_a[N];
int mn[N],mx[N];//A 树的子树区段
void pdfs(int u,int fa){
    B_dfn[u] = ++dfn;
    e[++tot] = B_dfn[u];
    p[B_dfn[u]] = tot;
    for(auto v:B[u]){
        if(v.first == fa)continue;
        rdis[v.first] = rdis[u] + v.second;
        pdfs(v.first,u);
        e[++tot] = B_dfn[u];
    }
}
void init(){
    for(int i=1;i<=tot;i++)ST[i][0] = e[i];
    for(int i=1;i<20;i++){
        for(int j=1;j<=tot;j++){
            ST[j][i] = ST[j][i-1];
            if(j+(1<<(i-1)) <= tot)ST[j][i] = min(ST[j][i-1],ST[j+(1<<(i-1))][i-1]);
        }
    }
}
int log(int len){return 63 - __builtin_clzll(len*1ull);}
int get_dis(int u,int v){
    if(u==v)return 0;
    //get lca
    int ret = 0;
    if(p[B_dfn[u]] > p[B_dfn[v]])swap(u,v);
    int k = log(p[B_dfn[v]] - p[B_dfn[u]] + 1);
    assert(k<20);
    int lca = min(ST[p[B_dfn[u]]][k],ST[p[B_dfn[v]] - (1<<k) + 1][k]);
    //get dis
    ret = rdis[u] + rdis[v] - 2*rdis[lca];
    return ret;
}

void dfs(int u,int fa){
    A_dfn[u] = ++dfn;
    to_a[dfn] = u;
    mn[u] = mx[u] = dfn;
    for(auto v:A[u]){
        if(v.first == fa)continue;
        a[v.first] = a[u] + v.second;
        dfs(v.first,u);
        mx[u] = max(mx[u],mx[v.first]);
    }
}

int p1[N<<2],p2[N<<2],w1[N<<2],w2[N<<2],lz[N<<2];

#define mid ((l+r)>>1)
#define ls (x<<1)
#define rs (x<<1|1)

void pushup(int x){
    int _p[4] = {p1[ls],p2[ls],p1[rs],p2[rs]};
    int _w[4] = {w1[ls],w2[ls],w1[rs],w2[rs]};
    int dis = 0,rp1 = 0,rp2 = 0,rw1 = 0,rw2 = 0;
    for(int i=0;i<3;i++){
        for(int j=i+1;j<4;j++){
            if(_p[i] == _p[j]){
                if(dis < _w[i]){
                    dis = _w[i];
                    rp1 = _p[i];rp2 = _p[j];
                    rw1 = _w[i];rw2 = _w[j];
                }
            }else{
                int d = get_dis(_p[i],_p[j]);
                if(dis < d + _w[i] + _w[j]){
                    dis = d + _w[i] + _w[j];
                    rp1 = _p[i];rp2 = _p[j];
                    rw1 = _w[i];rw2 = _w[j];
                }
            }
        }
    }
    p1[x] = rp1;p2[x] = rp2;
    w1[x] = rw1;w2[x] = rw2;
}
void pushdown(int x){
    int lazy = lz[x];
    lz[x] = 0;
    w1[ls] += lazy;w2[ls] += lazy;lz[ls] += lazy;
    w1[rs] += lazy;w2[rs] += lazy;lz[rs] += lazy;
}
void build(int x,int l,int r){
    if(l==r){
        p1[x] = p2[x] = to_a[l];
        w1[x] = w2[x] = a[to_a[l]];
        return ;
    }
    build(ls,l,mid);build(rs,mid+1,r);
    pushup(x);
}
void mdf(int x,int l,int r,int L,int R,int v){
    if(L<=l && r<=R){
        w1[x] += v;w2[x] += v;
        lz[x] += v;
        return ;
    }
    pushdown(x);
    if(L<=mid)mdf(ls,l,mid,L,R,v);
    if(r>mid)mdf(rs,mid+1,r,L,R,v);
    pushup(x);
}
void hg(int u,int fa){
    //statistics
    for(auto i:b[u]){
        ans[i.second] = max(get_dis(i.first,p1[1])+w1[1],get_dis(i.first,p2[1])+w2[1]);
    }
    for(auto v:A[u]){
        if(v.first==fa)continue;
        //in
        mdf(1,1,n,1,n,v.second);
        mdf(1,1,n,mn[v.first],mx[u],-2*v.second);
        hg(v.first,u);
        //out
        mdf(1,1,n,mn[v.first],mx[u],2*v.second);
        mdf(1,1,n,1,n,-v.second);
    }
}

void solve(){
    cin>>n>>q;
    for(int i=1,u,v,w;i<n;i++){
        cin>>u>>v>>w;
        A[u].push_back({v,w});
        A[v].push_back({u,w});
    }
    for(int i=1,u,v,w;i<n;i++){
        cin>>u>>v>>w;
        B[u].push_back({v,w});
        B[v].push_back({u,w});
    }
    for(int i=1,ta,tb;i<=q;i++){
        cin>>ta>>tb;
        b[ta].push_back({tb,i});
    }
    //预处理B树的树上距离
    pdfs(1,0);dfn=0;
    init();
    //线段树
    //求出根节点答案 build
    dfs(1,0);
    build(1,1,n);
    //换根

    hg(1,0);

    // cout<<p1[1]<<' '<<p2[1]<<' '<<w1[1]<<' '<<w2[1]<<endl;
    // cout<<get_dis(p1[1],p2[1]) + w1[1] + w2[1]<<endl;

    //输出
    for(int i=1;i<=q;i++)cout<<ans[i]<<'\n';
}
signed main(){
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    int aqx = 1;
    //cin>>aqx;
    while(aqx--)solve();
    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 7ms
memory: 97136kb

input:

3 4
1 2 1
2 3 2
1 2 2
2 3 1
1 1
1 2
2 1
2 2

output:

6
4
5
3

result:

ok 4 number(s): "6 4 5 3"

Test #2:

score: 0
Accepted
time: 8ms
memory: 98220kb

input:

2 1
1 2 1
1 2 1
1 1

output:

2

result:

ok 1 number(s): "2"

Test #3:

score: 0
Accepted
time: 11ms
memory: 98296kb

input:

2 1
1 2 1
1 2 1
1 2

output:

1

result:

ok 1 number(s): "1"

Test #4:

score: -100
Runtime Error

input:

10000 50000
8101 5996 108427744
5996 7605 870838849
5996 5599 603303696
8101 3006 339377417
8101 6463 442516687
6463 5560 109174079
5560 4063 127596224
3006 1682 947915262
5996 1986 130416311
6463 5455 279771516
6463 2634 516688796
4063 3034 217886863
7605 5092 742375061
5599 2266 193804402
5092 140...

output:


result: