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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#235189 | #6559. A Tree and Two Edges | ugly2333 | WA | 2ms | 10092kb | C++20 | 1.6kb | 2023-11-02 15:49:13 | 2023-11-02 15:49:14 |
Judging History
answer
//Δ_B
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef double DB;
const int N = 222222;
const int M = 22;
int n,m=20,q,a1,b1,a2,b2,f[N],d[N],g[N][M];
vector<int> v[N];
int fnd(int x){
if(f[x]==x)
return x;
return f[x]=fnd(f[x]);
}
void dfs(int u,int fa){
g[u][0]=fa;
d[u]=d[fa]+1;
int i,x;
for(i=0;i<v[u].size();i++){
x=v[u][i];
if(x!=fa)
dfs(x,u);
}
}
int lca(int x,int y){
int j;
if(d[x]>d[y])
swap(x,y);
for(j=20;j>=0;j--)
if(d[x]<=d[g[y][j]])
y=g[y][j];
if(x==y)
return x;
for(j=20;j>=0;j--)
if(g[x][j]!=g[y][j])
x=g[x][j],y=g[y][j];
return g[x][0];
}
int chk(int a,int b,int c){
int x=lca(a,b);
return !((lca(a,c)==c||lca(b,c)==c)&&lca(c,x)==x);
}
int chk2(int a1,int b1,int a2,int b2){
return chk(a1,b1,lca(a2,b2))&&chk(a2,b2,lca(a1,b1));
}
int chk3(int a1,int b1,int a2,int b2,int a3,int b3){
return chk2(a1,b1,a2,b2)&&chk2(a2,b2,a3,b3)&&chk2(a3,b3,a1,b1);
}
int main(){
int i,j,x,y;
scanf("%d%d",&n,&q);
for(i=1;i<=n;i++)
f[i]=i;
for(i=1;i<=n+1;i++){
scanf("%d%d",&x,&y);
if(fnd(x)==fnd(y)){
if(a1)
a2=x,b2=y;
else
a1=x,b1=y;
}
else{
v[x].push_back(y);
v[y].push_back(x);
f[fnd(y)]=x;
}
}
dfs(1,0);
for(j=1;j<=m;j++)
for(i=1;i<=n;i++)
g[i][j]=g[g[i][j-1]][j-1];
while(q--){
scanf("%d%d",&x,&y);
i=1;
i+=chk2(x,a1,b1,y)+chk2(x,b1,a1,y);
i+=chk2(x,a2,b2,y)+chk2(x,b2,a2,y);
i+=chk3(x,a1,b1,a2,b2,y)+chk3(x,b1,a1,a2,b2,y)+chk3(x,a1,b1,b2,a2,y)+chk3(x,b1,a1,b2,a2,y);
printf("%d\n",i);
}
return 0;
}
Details
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Test #1:
score: 0
Wrong Answer
time: 2ms
memory: 10092kb
input:
4 6 1 2 1 3 1 4 2 3 2 4 1 2 1 3 1 4 2 3 2 4 3 4
output:
3 2 3 3 3 4
result:
wrong answer 2nd lines differ - expected: '3', found: '2'