Submission #1032905

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032905		Malix	The Xana coup (BOI21_xanadu)	C++14	30 / 100	111 ms	18880 KiB

xanadu

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

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> tii;
typedef vector<ll> li;
typedef vector<li> lii;

#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define LSOne(s) ((s)&(-s))

ll INF=1e18+10;
int inf=1e7+10;
ll M=1e9+7;

int n;
vii a;
vector<vii> dp;
vi p,b;

void solve(int node){
    int o1=inf,o2=inf,e1=0,e2=0;int k=0;
    for(auto u:a[node]){
        if(p[node]==u)continue;k++;
        p[u]=node;
        solve(u);
        int o1t=min(o1+dp[0][1][u],e1+dp[1][1][u]);
        int o2t=min(o2+dp[0][0][u],e2+dp[1][0][u]);
        int e1t=min(e1+dp[0][1][u],o1+dp[1][1][u]);
        int e2t=min(e2+dp[0][0][u],o2+dp[1][0][u]);
        o1=o1t;o2=o2t;e1=e1t;e2=e2t;
    }
    if(b[node]==0){
        dp[0][0][node]=e2;
        dp[1][0][node]=1+o1;
        dp[1][1][node]=1+e1;
        dp[0][1][node]=o2;
    }
    else{
        dp[0][0][node]=o2;
        dp[1][0][node]=1+e1;
        dp[1][1][node]=1+o1;
        dp[0][1][node]=e2;
    }
}

int main() {   
//ios::sync_with_stdio(0);
//cin.tie(0);
//freopen("test_input.txt", "r", stdin);
//freopen("test_output.txt", "w", stdout);
   cin>>n;
   a.resize(n);p.resize(n,-1);b.resize(n);
   dp.resize(2,vii(2,vi(n)));
   REP(i,0,n-1){
    int x,y;
    cin>>x>>y;
    x--;y--;
    a[x].PB(y);
    a[y].PB(x);
   }
   REP(i,0,n)cin>>b[i];
   solve(0);
   cerr<<dp[0][0][0]<<" "<<dp[1][0][0]<<"\n";
   int ans=min(dp[0][0][0],dp[1][0][0]);
   if(ans>=inf)cout<<"impossible";
   else cout<<ans;
}

Compilation message (stderr)

xanadu.cpp: In function 'void solve(int)':
xanadu.cpp:32:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   32 |         if(p[node]==u)continue;k++;
      |         ^~
xanadu.cpp:32:32: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   32 |         if(p[node]==u)continue;k++;
      |                                ^

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