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QOJ
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 |
---|---|---|---|---|---|---|---|---|---|
#58001 | #3711. Floyd-Warshall | zjy2022 | WA | 5ms | 16884kb | C++ | 1.5kb | 2022-10-24 08:28:41 | 2022-10-24 08:29:03 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> PII;
inline int read(){
int x=0,f=1;char ch;
while(!isdigit(ch=getchar()))if(ch=='-')f=-f;
do x=(x<<3)+(x<<1)+(ch^48);while(isdigit(ch=getchar()));
return x*f;
}
const int N=1e5+5;
int n,m,q,cnt;
int dis[105][N],vis[N];
int f[N][18];
vector<int>G[N];
void bfs(int st){
++cnt;
queue<int>Q;
Q.push(st);
while(!Q.empty()){
int x=Q.front();Q.pop();
for(int v:G[x])
if(v!=st&&!dis[cnt][v])
dis[cnt][v]=dis[cnt][x]+1,Q.push(v);
}
}
void dfs(int x,int fa){
dis[0][x]=dis[0][fa]+1,f[x][0]=fa;
for(int i=0;f[x][i];++i)
f[x][i+1]=f[f[x][i]][i];
for(int v:G[x]){
if(v==fa)continue;
if(dis[0][v]&&dis[0][v]<dis[0][x])bfs(x);
else dfs(v,x);
}
}
int LCA(int x,int y){
if(dis[0][x]<dis[0][y])swap(x,y);
for(int h=dis[0][x]-dis[0][y],i=0;h;h>>=1,++i)
if(h&1)x=f[x][i];
if(x==y)return x;
for(int i=17;~i;--i)
if(f[x][i]!=f[y][i])
x=f[x][i],y=f[y][i];
return f[x][0];
}
int query(int u,int v){
int res=dis[0][u]+dis[0][v]-2*dis[0][LCA(u,v)];
for(int i=1;i<=cnt;++i)res=min(res,dis[i][u]+dis[i][v]);
return res;
}
signed main(){
n=read(),m=read(),q=read();
for(int i=1;i<=m;++i){
int u=read(),v=read();
G[u].push_back(v),G[v].push_back(u);
}
dfs(1,0);
for(int i=1;i<=q;++i){
int u=read(),v=read();
printf("%d\n",query(u,v));
}
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 2ms
memory: 12016kb
input:
4 5 3 1 2 1 3 1 4 2 3 3 4 2 2 2 3 2 4
output:
0 1 2
result:
ok 3 number(s): "0 1 2"
Test #2:
score: 0
Accepted
time: 3ms
memory: 8440kb
input:
1 2 1 1 1 1 1 1 1
output:
0
result:
ok 1 number(s): "0"
Test #3:
score: -100
Wrong Answer
time: 5ms
memory: 16884kb
input:
5 7 10 5 3 1 2 4 1 2 5 3 4 2 2 1 3 5 5 4 5 3 2 4 4 5 3 3 5 2 4 4 2 5 3 4 2
output:
0 2 -4 0 1 1 -3 -3 1 -3
result:
wrong answer 3rd numbers differ - expected: '2', found: '-4'