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답안 #870898

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
870898 2023-11-09T12:21:41 Z Rafi22 Svjetlo (COCI20_svjetlo) C++14
110 / 110
 1102 ms 358696 KB 
#include <bits/stdc++.h>

#define ll long long
#define ld double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
using namespace std;
int inf=1000000007;
int mod=1000000007;
int mod1=998244353;

const int N=500007;

vector<int>G[N];
int t[N];
bool is[N];
int DP[N][2][2];

void dfs(int v,int o)
{
    t[v]=!is[v];
    for(int i=0;i<2;i++) for(int j=0;j<2;j++) DP[v][i][j]=inf;
    DP[v][is[v]^1][0]=1;
    for(auto u:G[v])
    {
        if(u==o) continue;
        dfs(u,v);
        t[v]+=t[u];
        if(t[u]==0) continue;
        vector<vector<int>>nDP(2,vector<int>(2,inf));
        for(int x=0;x<2;x++)
        {
            for(int a=0;a<2;a++)
            {
                for(int y=0;y<2;y++)
                {
                    for(int b=0;b<2;b++)
                    {
                        if(a&&b) continue;
                        int X=x,C=0;
                        if(y==0)
                        {
                            C+=2;
                            X^=1;
                        }
                        if(!b)
                        {
                            C++;
                            X^=1;
                        }
                        nDP[X][a|b]=min(nDP[X][a|b],DP[v][x][a]+DP[u][y][b]+C);
                    }
                }
            }
        }
        for(int x=0;x<2;x++) for(int a=0;a<2;a++) DP[v][x][a]=nDP[x][a];
    }
    DP[v][0][1]=min(DP[v][0][1],DP[v][0][0]);
    DP[v][1][1]=min(DP[v][1][1],DP[v][1][0]);
}

vector<int>P[N][2][2];
vector<int>S[N][2][2];
int mem[N][2][2];

int ans=inf;
void dfs1(int v,int o)
{
    ans=min(ans,DP[v][1][1]);
    //cout<<v<<" "<<DP[v][1][1]<<endl;
    //liczymy P,S;
    for(int x=0;x<2;x++) for(int a=0;a<2;a++) S[v][x][a].resize(sz(G[v])+2,inf);
    for(int x=0;x<2;x++) for(int a=0;a<2;a++) P[v][x][a].resize(sz(G[v])+2,inf);
    P[v][is[v]^1][0][0]=1;
    for(int i=1;i<=sz(G[v]);i++)
    {
        int u=G[v][i-1];
        if(t[u]==0)
        {
            for(int x=0;x<2;x++) for(int a=0;a<2;a++) P[v][x][a][i]=P[v][x][a][i-1];
        }
        else
        {
            for(int x=0; x<2; x++)
            {
                for(int a=0; a<2; a++)
                {
                    for(int y=0; y<2; y++)
                    {
                        for(int b=0; b<2; b++)
                        {
                            if(a&&b) continue;
                            int X=x,C=0;
                            if(y==0)
                            {
                                C+=2;
                                X^=1;
                            }
                            if(!b)
                            {
                                C++;
                                X^=1;
                            }
                            P[v][X][a|b][i]=min(P[v][X][a|b][i],P[v][x][a][i-1]+DP[u][y][b]+C);
                        }
                    }
                }
            }
        }
    }
    S[v][0][0][sz(G[v])+1]=0;
    for(int i=sz(G[v]);i>0;i--)
    {
        int u=G[v][i-1];
        if(t[u]==0)
        {
            for(int x=0;x<2;x++) for(int a=0;a<2;a++) S[v][x][a][i]=S[v][x][a][i+1];
        }
        else
        {
            for(int x=0; x<2; x++)
            {
                for(int a=0; a<2; a++)
                {
                    for(int y=0; y<2; y++)
                    {
                        for(int b=0; b<2; b++)
                        {
                            if(a&&b) continue;
                            int X=x,C=0;
                            if(y==0)
                            {
                                C+=2;
                                X^=1;
                            }
                            if(!b)
                            {
                                C++;
                                X^=1;
                            }
                            S[v][X][a|b][i]=min(S[v][X][a|b][i],S[v][x][a][i+1]+DP[u][y][b]+C);
                        }
                    }
                }
            }
        }
    }
    for(int i=1;i<=sz(G[v]);i++)
    {
        int u=G[v][i-1];
        if(u==o) continue;
        for(int x=0;x<2;x++) for(int a=0;a<2;a++) DP[v][x][a]=inf;
        for(int x=0; x<2; x++)
        {
            for(int a=0; a<2; a++)
            {
                for(int y=0; y<2; y++)
                {
                    for(int b=0; b<2; b++)
                    {
                        if(a&&b) continue;
                        DP[v][x^y][a|b]=min(DP[v][x^y][a|b],P[v][x][a][i-1]+S[v][y][b][i+1]);
                    }
                }
            }
        }
        t[v]-=t[u];
        t[u]+=t[v];
        for(int x=0;x<2;x++) for(int a=0;a<2;a++) mem[u][x][a]=DP[u][x][a];
        if(t[v]>0)
        {
            vector<vector<int>>nDP(2,vector<int>(2,inf));
            for(int x=0; x<2; x++)
            {
                for(int a=0; a<2; a++)
                {
                    for(int y=0; y<2; y++)
                    {
                        for(int b=0; b<2; b++)
                        {
                            if(a&&b) continue;
                            int X=x,C=0;
                            if(y==0)
                            {
                                C+=2;
                                X^=1;
                            }
                            if(!b)
                            {
                                C++;
                                X^=1;
                            }
                            nDP[X][a|b]=min(nDP[X][a|b],DP[u][x][a]+DP[v][y][b]+C);
                        }
                    }
                }
            }
            for(int x=0; x<2; x++) for(int a=0; a<2; a++) DP[u][x][a]=nDP[x][a];
        }
        dfs1(u,v);
    }
    for(int x=0;x<2;x++) for(int a=0;a<2;a++) DP[v][x][a]=mem[v][x][a];
    t[v]-=t[o];
    t[o]+=t[v];
}


signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n,a,b;
    string s;
    cin>>n>>s;
    for(int i=0;i<n;i++) is[i+1]=s[i]-'0';
    for(int i=1;i<n;i++)
    {
        cin>>a>>b;
        G[a].pb(b);
        G[b].pb(a);
    }
    dfs(1,0);
    dfs1(1,0);
    cout<<ans;


    return 0;
}

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 111700 KB Output is correct
2 Correct 25 ms 111780 KB Output is correct
3 Correct 25 ms 111708 KB Output is correct
4 Correct 26 ms 111704 KB Output is correct
5 Correct 25 ms 111708 KB Output is correct
6 Correct 28 ms 111708 KB Output is correct
7 Correct 24 ms 111752 KB Output is correct
8 Correct 27 ms 111708 KB Output is correct
9 Correct 24 ms 111688 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 779 ms 262112 KB Output is correct
2 Correct 1102 ms 343476 KB Output is correct
3 Correct 1102 ms 358696 KB Output is correct
4 Correct 969 ms 300784 KB Output is correct
5 Correct 1065 ms 328504 KB Output is correct

Subtask #3
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 892 ms 236076 KB Output is correct
2 Correct 1084 ms 269300 KB Output is correct
3 Correct 1018 ms 271200 KB Output is correct
4 Correct 823 ms 248232 KB Output is correct
5 Correct 919 ms 270348 KB Output is correct
6 Correct 963 ms 259376 KB Output is correct
7 Correct 912 ms 278820 KB Output is correct

Subtask #4
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 111700 KB Output is correct
2 Correct 25 ms 111780 KB Output is correct
3 Correct 25 ms 111708 KB Output is correct
4 Correct 26 ms 111704 KB Output is correct
5 Correct 25 ms 111708 KB Output is correct
6 Correct 28 ms 111708 KB Output is correct
7 Correct 24 ms 111752 KB Output is correct
8 Correct 27 ms 111708 KB Output is correct
9 Correct 24 ms 111688 KB Output is correct
10 Correct 779 ms 262112 KB Output is correct
11 Correct 1102 ms 343476 KB Output is correct
12 Correct 1102 ms 358696 KB Output is correct
13 Correct 969 ms 300784 KB Output is correct
14 Correct 1065 ms 328504 KB Output is correct
15 Correct 892 ms 236076 KB Output is correct
16 Correct 1084 ms 269300 KB Output is correct
17 Correct 1018 ms 271200 KB Output is correct
18 Correct 823 ms 248232 KB Output is correct
19 Correct 919 ms 270348 KB Output is correct
20 Correct 963 ms 259376 KB Output is correct
21 Correct 912 ms 278820 KB Output is correct
22 Correct 906 ms 252900 KB Output is correct
23 Correct 979 ms 260536 KB Output is correct
24 Correct 889 ms 254500 KB Output is correct
25 Correct 850 ms 246872 KB Output is correct
26 Correct 922 ms 281988 KB Output is correct
27 Correct 875 ms 279528 KB Output is correct
28 Correct 707 ms 258788 KB Output is correct
29 Correct 1101 ms 277080 KB Output is correct
30 Correct 841 ms 266296 KB Output is correct