Submission #1037100

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037100		8pete8	Parachute rings (IOI12_rings)	C++17	37 / 100	719 ms	120692 KiB

rings

#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<cassert>
#include<unordered_map>
#include <queue>
#include <cstdint>
#include<cstring>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include <iomanip>
#include<numeric>
#include<bitset>
using namespace std;
#define ll long long
#define f first
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-lopps")
using namespace std;
const int mod=1e9+7,mxn=1e6+5,inf=1e9,minf=-1e9,lg=25;
int n,vis[mxn+10];
vector<int>adj[mxn+10];
int ans;
void Init(int N_) {
  n=N_;
}
void Link(int a,int b){
  adj[a].pb(b);
  adj[b].pb(a);
}
int add[mxn+10],rem[mxn+10],cnt=0,valid[mxn+10],on[mxn+10];
void dfs(int cur,int p){
  vis[cur]=on[cur]=1;
  for(auto i:adj[cur]){
    if(i==p)continue;
    if(vis[i]&&on[i])add[cur]++,rem[i]++,cnt++;
    if(!vis[i])dfs(i,cur),add[cur]+=(add[i]-rem[i]);
  }
  on[cur]=0;
}
int CountCritical(){
  cnt=0;
  int mx=0;
  for(int i=0;i<n;i++)add[i]=0,on[i]=0,vis[i]=0;
  for(int i=0;i<n;i++){
    if(!vis[i])dfs(i,-1);
    mx=max(mx,add[i]);
  }
  if(cnt>1)return 0;//atmost 1 comp with cycle
  int node=-1,have=0;
  for(int i=0;i<n;i++)if(adj[i].size()>=3)have++;
  int cnt=0;
  for(int i=0;i<n;i++){
    int x=(adj[i].size()>=3);
    for(auto j:adj[i])if(adj[j].size()==3)x++;
    if(x==have&&add[i]==mx)cnt++;
  }
  return cnt;
}

/*
if we can find intersect from all these set:
1. in every cycle
2. have deg >=3
3. directly connected to deg 3
if there are no deg>3 then there can be atmost 4 candidates
because the node has to be directly connected to all deg 3 and every node deg<=3
if theres a node deg>3 we just have to check 1 node but the deg can be a lot

how to know if a node is in cycle?
*/

Compilation message (stderr)

rings.cpp:32:40: warning: bad option '-funroll-lopps' to pragma 'optimize' [-Wpragmas]
   32 | #pragma GCC optimize ("03,unroll-lopps")
      |                                        ^
rings.cpp:38:17: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   38 | void Init(int N_) {
      |                 ^
rings.cpp:41:22: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   41 | void Link(int a,int b){
      |                      ^
rings.cpp:46:23: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   46 | void dfs(int cur,int p){
      |                       ^
rings.cpp:55:19: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   55 | int CountCritical(){
      |                   ^
rings.cpp: In function 'int CountCritical()':
rings.cpp:64:7: warning: unused variable 'node' [-Wunused-variable]
   64 |   int node=-1,have=0;
      |       ^~~~

• Subtask 1: 20 / 20
• Subtask 2: 17 / 17
• Subtask 3: 0 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31