#include "dreaming.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define all(v) v.begin(),v.end()
#define OVL(x,s) for(auto y:x) cout<<y<<s; cout<<"\n";
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__);
#define pb push_back
#define F first
#define S second
const int MAXN=1e5+100;
int n,m,l;
vector<vector<pair<int,int>>> v(MAXN);
vector<vector<ll>> diameters;
bool visited[MAXN];
ll parr[MAXN];
ll depth[MAXN];
pair<ll,ll> dfs(int node,int par,ll ew=0){//depth, best node
visited[node]=true;
parr[node]=par;
depth[node]=ew;
if(v[node].size()==1&&v[node][0].F==par){
return {ew,node};
}
ll ans=0;
ll best=0;
for(auto x:v[node]){
if(x.F!=par){
pair<ll,ll> p=dfs(x.F,node,ew+x.S);
if(p.F>ans){
ans=p.F;
best=p.S;
}
}
}
return {ans,best};
}
ll bigdia=0;
void find_diameter(int node){
pair<ll,ll> p=dfs(node,node);
int f=p.S;
memset(parr,-1,sizeof(parr));
p=dfs(p.S,p.S);
// dbg(f,p.S);
vector<ll> dia;
while(p.S!=parr[p.S]) {
dia.push_back(p.S);
p.S=parr[p.S];
}
dia.push_back(p.S);
reverse(all(dia));
diameters.push_back(dia);
bigdia=p.F;
}
struct Edge{
ll a,b;
ll c;
bool operator < (const Edge& other) const{
return c<other.c;
}
};
int find(int node){
if(node==parr[node]) return node;
return parr[node]=find(parr[node]);
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
n=N;
m=M;
l=L;
memset(visited,false,sizeof(visited));
for(int i=0;i<m;i++){
v[A[i]].push_back({B[i],T[i]});
v[B[i]].push_back({A[i],T[i]});
}
memset(depth,0,sizeof(depth));
for(int i=0;i<n;i++){
if(!visited[i]){
find_diameter(i);
}
}
vector<Edge> edges;
int d=diameters.size();
set<pair<int,int>> p;
sort(all(diameters),[&](auto a,auto b){
return a.size()<b.size();
});
for(int i=0;i+1<d;i++){
for(int j=0;j<diameters[i].size();j++){
int x=diameters[i][j];
int y=diameters[i+1][j];
int a,b,c,e;
a=depth[diameters[i].back()]-depth[x];
b=depth[x];
c=depth[diameters[i+1].back()]-depth[y];
e=depth[y];
int cc=max(a,b);
int dd=max(c,e);
edges.push_back({.a=x,.b=y,.c=cc+l+dd});
}
}
sort(all(edges));
for(int i=0;i<n;i++) parr[i]=i;
for(auto x:diameters){
for(auto y:x) {
parr[y]=x[0];
}
}
for(auto& edge:edges){
if(find(edge.a)==find(edge.b)) continue;
int a=find(edge.a);
int b=find(edge.b);
parr[b]=a;
// dbg(a,b,edge.a,edge.b);
v[edge.a].pb({edge.b,l});
v[edge.b].pb({edge.a,l});
}
memset(depth,0LL,sizeof(depth));
find_diameter(0);
// OVL(diameters.back()," ")
return bigdia;
}
#ifdef IOI
#define fail(s, x...) do { \
fprintf(stderr, s "\n", ## x); \
exit(1); \
} while(0)
#define MAX_N 100000
static int A[MAX_N];
static int B[MAX_N];
static int T[MAX_N];
int main() {
int N, M, L, i;
int res;
FILE *f = fopen("dreaming.in", "r");
if (!f)
fail("Failed to open input file.");
res = fscanf(f, "%d%d%d", &N, &M, &L);
for (i = 0; i < M; i++)
res = fscanf(f, "%d%d%d", &A[i], &B[i], &T[i]);
fclose(f);
int answer = travelTime(N, M, L, A, B, T);
printf("%d\n", answer);
return 0;
}
#endif
Compilation message
dreaming.cpp: In function 'void find_diameter(int)':
dreaming.cpp:43:9: warning: unused variable 'f' [-Wunused-variable]
43 | int f=p.S;
| ^
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:90:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
90 | for(int j=0;j<diameters[i].size();j++){
| ~^~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
59 ms |
17776 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
4308 KB |
Output is correct |
| 2 |
Correct |
2 ms |
4308 KB |
Output is correct |
| 3 |
Incorrect |
2 ms |
4276 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
59 ms |
17776 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
825 ms |
13492 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
4308 KB |
Output is correct |
| 2 |
Correct |
2 ms |
4308 KB |
Output is correct |
| 3 |
Incorrect |
2 ms |
4276 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
59 ms |
17776 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
