제출 #505073

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
505073		tgbegimx	무제 (POI11_dyn)	C++17	100 / 100	1341 ms	37856 KiB

Main

#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(0) ; cin.tie(0);cout.tie(0)
#define ll long long
#define foru(i,l,r) for(int i=l;i<=r;++i)
#define ford(i,l,r) for(int i=l;i>=r;--i)
#define pb push_back
using namespace std;
const int N=3e5+10;
vector<int> d;
vector<vector<int>> ke;
int dp[N],dem,kt[N];
int n,m;
int read()
{
    int s=0,f=1;
    char ch=getchar();
    for(;ch<'0'||ch>'9';f=(ch=='-')?-1:f,ch=getchar());
    for(;ch>='0'&&ch<='9';s=s*10+(ch^48),ch=getchar());
    return s*f;
}
void dfs(int k,int u,int fa)
{
    int mx1=-1e9,mx2=-1e9;
    if(d[u]) mx1=0;
    //if(k>m) return;
    for(auto v:ke[u])
    {
        if(v==fa) continue;
        //cout<<v<<' ';
        dfs(k,v,u);
        if(kt[v]==1) mx1=max(mx1,dp[v]+1);
        if(kt[v]==2) mx2=max(mx2,dp[v]-1);
        if(kt[v]==-1||dem>m) {kt[u]==-1;return;}
    }
    if(mx1>mx2)
    {
        if(mx1>=k)
        {
          ++dem;
          kt[u]=2;
          dp[u]=k;
          if(dem>m) {kt[u]=-1;return;}
        }
        else kt[u]=1,dp[u]=mx1;
    }
    else kt[u]=2,dp[u]=mx2;
}
bool check(int k)
{
    dem=0;
    dfs(k,1,1);
    if(kt[1]==-1) return 0;
    if(kt[1]==1&&dp[1]>=0) ++dem;
    return dem<=m;
}
void solve()
{
    n=read(),m=read();
    d.resize(n+1);
    ke.resize(n+1);
    foru(i,1,n) d[i]=read();
    foru(i,1,n-1)
    {
        int u,v;
        u=read(),v=read();
        ke[u].pb(v);
        ke[v].pb(u);
    }
    //for(auto v:ke[5]) cout<<v<<' ';
    int l=0,r=n,ans=0;
    while(l<=r)
    {
        int mid=(l+r)>>1;
        if(check(mid)) ans=mid,r=mid-1;
        else l=mid+1;
    }
    printf("%d",ans);
}
int main()
{
    //freopen("main.inp","r",stdin);
    //freopen("main.out","w",stdout);
    //fast;
    solve();

}

컴파일 시 표준 에러 (stderr) 메시지

dyn.cpp: In function 'void dfs(int, int, int)':
dyn.cpp:33:36: warning: statement has no effect [-Wunused-value]
   33 |         if(kt[v]==-1||dem>m) {kt[u]==-1;return;}
      |                               ~~~~~^~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10