Submission #1084931

#	Time	Username	Problem	Language	Result	Execution time	Memory
1084931		modwwe	The Xana coup (BOI21_xanadu)	C++17	100 / 100	47 ms	19804 KiB

xanadu

#pragma GCC optimize("Ofast,unroll-loops")
#include<bits/stdc++.h>
#define int long long
//#define ll long long
#define down cout<<'\n';
#define debug cout<<" cucuucucuuu",down
#define NHP     ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe  int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define pb push_back
#define checktime   cerr << (double)clock() / CLOCKS_PER_SEC * 1000  << " ms";
using namespace std;
#define getchar_unlocked getchar

inline int scan()
{
    char c = getchar_unlocked();
    int x = 0;
    while(c<'0'||c>'9')
    {
        c=getchar_unlocked();
    }
    while(c>='0'&&c<='9')
    {
        x=(x<<1)+(x<<3)+c-'0';
        c=getchar_unlocked();
    }
    return x;
}

void phongbeo();
const int inf=1e9;
const int mod2=998244353;
const int  mod1=998244353;
struct icd
{
    long double a;
    int b;
};
struct ib
{
    int a;
    int b;
};
struct ic
{
    int a,b,c;
};
struct id
{
    int a,b,c,d;
};
struct ie
{
    int a,b,c,d,e;

};

int n,m,s1,s2,s4,s3,sf,k,s5,s6,mx,s7,s8,s9,mx2,res,dem2=0,dem=0,s33,dem3,dem4,l,r,mid,l2,r2,center;
int  i,s10,s12;
int kk;
int el=29;

main()
{
#ifndef ONLINE_JUDGE
///    fin(task),fou(task);
#endif
    NHP
    /// cin>>s1;
///modwwe
    phongbeo(),down
//checktime
}
int dp[100001][2][2];
bool b[100001];
vector<int> v[100001];
void dfs(int x,int y)
{
    /// 0 0 no tat cac con no tat
    /// 0 1 no tat cac con no bat
    /// 1 0 no bat cac con no tat
    /// 1 1 no va cac con bat
    dp[x][b[x]][1]=0;
    dp[x][1-b[x]][1]=1e12;
    dp[x][1-b[x]][0]=1e12;
    dp[x][b[x]][0]=0;
    for(auto f:v[x])
    {
        if(f!=y)
        {
            dfs(f,x);
            s2=dp[x][0][0];
            s3=dp[x][0][1];
            s4=dp[x][1][0];
            s5=dp[x][1][1];
            dp[x][0][0]=min({dp[x][0][0]+dp[f][0][0],s4+dp[f][1][1]+1});
            dp[x][1][0]=min({dp[x][1][0]+dp[f][0][0],s2+dp[f][1][1]+1});
            dp[x][0][1]=min({dp[x][0][1]+dp[f][1][0],s5+dp[f][0][1]+1});
            dp[x][1][1]=min({dp[x][1][1]+dp[f][1][0],s3+dp[f][0][1]+1});
        }
    }
    if(y==0)
        dp[1][0][0]=min(dp[1][0][0],dp[1][1][1]+1);
}
void phongbeo()
{
    cin>>n;
    for(int i=1; i<n; i++)
        cin>>l>>r,v[l].pb(r),v[r].pb(l);
    for(int i=1; i<=n; i++)
        cin>>b[i];
    dfs(1,0);
    if(dp[1][0][0]<=1e12)
        cout<<dp[1][0][0];
    else cout<<"impossible";

}

Compilation message (stderr)

xanadu.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   68 | main()
      | ^~~~

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