Submission #501762

#	Time	Username	Problem	Language	Result	Execution time	Memory
501762		tmn2005	Biochips (IZhO12_biochips)	C++17	0 / 100	14 ms	23768 KiB

biochips

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;

#define ar array
#define fr first
#define sc second

#define vec vector
#define ret return

#define ins insert
#define mk make_pair
#define pb push_back
#define pf push_front
#define pob pop_back
#define pof pop_front

#define int long long

#define pii pair<int,int>

#define all(s) s.begin(), s.end()
#define allr(s) s.rbegin(), s.rend()

#define NeedForSpeed ios::sync_with_stdio(0),cin.tie(0);
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
const int N=1e6+12,INF=1e9,mod = 1e9+7;
bool iswowel(char n){ n = toupper(n); if(n == 'A' || n == 'O' || n == 'U' || n == 'E' || n == 'I') return true; else return false;}
int n,m,k,x,y,l,r,o,timer,ans,res,ok,mx,mn = INF;
int a[N], tin[N], tout[N], up[N][30], b, c;
vec<int> g[N];

void dfs(int v, int pred){
	tin[v] = timer++;
	up[v][0] = pred;
	for(int i=1; i<=30; i++)
		up[v][i] = up[up[v][i-1]][i-1];
		
	for(int to : g[v]){
		if(to != pred){
			dfs(to, v);
		}
	}
	tout[v] = timer++;
}
bool upper(int a,int b){
	ret tin[a] <= tin[b] && tout[b] <= tout[a];
}
//int lca(int a, int b){
//	if(upper(a, b))ret a;
//	if(upper(b, a))ret b;
//	for(int i=30; i>=0; i--){
//		if(!upper(up[a][i], b)){
//			a = up[a][i];
//		}
//	}
//	ret up[a][0];
//}
main(){
	NeedForSpeed
    cin>>n>>k;
    for(int i=1; i<=n; i++){
    	cin>>x>>a[i];
    	g[x].pb(i);
	}
	dfs(0, 0);
	for(int mask=0; mask<(1<<n); mask++){
		if(__builtin_popcount(mask) == k){
			vec<int>v;
			for(int i=0; i<n; i++){
				if(((1<<i) & mask)){
					v.pb(i+1);
				}	
			}
			ok = 1;
			for(int i=0; i<k; i++){
				for(int j=i+1; j<k; j++){
					if(upper(v[i], v[j]) || upper(v[j], v[i])){
						ok = 0;
						break;
					}
				}
				if(!ok)break;
			}
			if(ok){
				ans = 0;
				for(int i=0; i<k; i++){
					ans += a[v[i]];
				}
				res = max(res, ans);
			}
		}
	}
	cout<<res<<endl;



	return 0;
}

Compilation message (stderr)

biochips.cpp:61:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   61 | main(){
      | ^~~~
biochips.cpp: In function 'void dfs(long long int, long long int)':
biochips.cpp:39:12: warning: iteration 29 invokes undefined behavior [-Waggressive-loop-optimizations]
   39 |   up[v][i] = up[up[v][i-1]][i-1];
      |   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
biochips.cpp:38:16: note: within this loop
   38 |  for(int i=1; i<=30; i++)
      |               ~^~~~

• Subtask 1: 0 / 100