#include<stdio.h>
#include<vector>
#include<algorithm>
using namespace std;
typedef pair<int,int> P;
int n, m, l;
vector<P> lst[100005];
int rd[100005], rcnt, diameter, dv;
int par[100005], dist[100005], res;
bool check[100005];
void dfs(int v, int prev, int d)
{
dist[v]=d;
par[v]=prev;
if(d>diameter) diameter=d, dv=v;
check[v]=true;
for(int i=0 ; i<lst[v].size() ; i++)
{
int nxt=lst[v][i].first;
int dst=lst[v][i].second;
if(nxt!=prev) dfs(nxt,v,d+dst);
}
}
void solve()
{
for(int i=rcnt ; i>1 ; i--)
{
int val=rd[i]+rd[i-1]+l;
if(val>res) res=val, rd[i-1]=max(rd[i],rd[i-1]+l);
else break;
}
}
int travelTime(int N, int M, int L, int A[], int B[], int T[])
{
n=N, m=M, l=L;
for(int i=0 ; i<m ; i++)
{
int v1, v2, d;
v1=A[i], v2=B[i], d=T[i];
lst[v1].push_back(P(v2,d));
lst[v2].push_back(P(v1,d));
}
for(int i=0 ; i<n ; i++)
{
if(!check[i])
{
rcnt++;
diameter=-1, dv=0;
dfs(i,-1,0);
int v1=dv;
diameter=-1;
dfs(v1,-1,0);
int v2=dv, gap=1e9+7;
while(v2!=-1)
{
int val=abs(diameter-dist[v2]*2);
if(val<gap)
{
gap=val;
rd[rcnt]=max(diameter-dist[v2],dist[v2]);
}
v2=par[v2];
}
res=max(res,diameter);
}
}
sort(rd+1,rd+1+rcnt);
solve();
return res;
}
Compilation message
dreaming.cpp: In function 'void dfs(int, int, int)':
dreaming.cpp:20:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0 ; i<lst[v].size() ; i++)
~^~~~~~~~~~~~~~
/tmp/cccjaUVD.o: In function `main':
grader.c:(.text.startup+0xa2): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
