Submission #414721

#	Time	Username	Problem	Language	Result	Execution time	Memory
414721		juggernaut	The Xana coup (BOI21_xanadu)	C++17	0 / 100	1092 ms	269040 KiB

xanadu

#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
typedef long long ll;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef IOI2021SG
    #define printl(args...)printf(args)
#else
    #define printl(args...)((void)0)
#endif
map<ll,int>mp;
vector<int>g[100005];
int n;
int run(ll mask){
    if(mp.count(mask))return mp[mask];
    mp[mask]=2e9;
    for(int i=0;i<n;i++){
        ll new_mask=mask;
        for(int to:g[i])new_mask^=(1ll<<to);
        umin(mp[mask],run(new_mask)+1);
    }
    return mp[mask];
}
int main(){
    scanf("%d",&n);
    for(int i=1;i<n;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        x--;y--;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    ll mask=0;
    for(int i=0;i<n;i++){
        int x;
        scanf("%d",&x);
        mask|=((1ll*x)<<i);
        g[i].push_back(i);
    }
    mp[mask]=0;
    int x=run(0);
    if(x==int(2e9))puts("impossible");
    else printf("%d",x);
}

Compilation message (stderr)

xanadu.cpp: In function 'void usaco(std::string)':
xanadu.cpp:5:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xanadu.cpp:5:66: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xanadu.cpp: In function 'int main()':
xanadu.cpp:34:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
xanadu.cpp:37:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         scanf("%d%d",&x,&y);
      |         ~~~~~^~~~~~~~~~~~~~
xanadu.cpp:45:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         scanf("%d",&x);
      |         ~~~~~^~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30