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답안 #972604

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
972604 2024-04-30T18:24:22 Z kl0989e The Xana coup (BOI21_xanadu) C++17
100 / 100
 60 ms 22540 KB 
#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define fi first
#define se second
#define pb push_back
#define vi vector<int>
#define pi pair<int, int>
#define all(x) (x).begin(),(x).end()

const int maxn=1e5+10;
vector<vi> graph(maxn);
vector<vi> dp(maxn,vi(4,1e9));// (on,on), (off,off), (off,on), (on,off)
vi onoff(maxn,0);

void dfs(int cur, int prev=-1) {
    if (graph[cur].size()==1 && cur!=0) {
        if (onoff[cur]) {
            dp[cur][0]=0;
            dp[cur][2]=0;
        }
        else {
            dp[cur][1]=0;
            dp[cur][3]=0;
        }
        return;
    }
    int sum1=0,sum2=0;
    int sig1=1,sig2=1;//1=on & 0=off
    int minc1=1e9,minc2=1e9;
    if (!onoff[cur]) {
        sig1=0;
        sig2=0;
    }
    for (auto to:graph[cur]) {
        if (to==prev) {
            continue;
        }
        dfs(to,cur);
        if (dp[to][0]+1<dp[to][1]) {
            sig1=1-sig1;
            sum1+=dp[to][0]+1;
            minc1=min(minc1,dp[to][1]-dp[to][0]-1);
        }
        else {
            sum1+=dp[to][1];
            minc1=min(minc1,dp[to][0]+1-dp[to][1]);
        }
        if (dp[to][3]+1<dp[to][2]) {
            sig2=1-sig2;
            sum2+=dp[to][3]+1;
            minc2=min(minc2,dp[to][2]-dp[to][3]-1);
        }
        else {
            sum2+=dp[to][2];
            minc2=min(minc2,dp[to][3]+1-dp[to][2]);
        }
        sum1=min(int(1e9),sum1);
        sum2=min(int(1e9),sum2);
    }
    //cout << "cur: " << cur << '\n' << sig1 << ' ' << sum1 << ' ' << minc1 << '\n' << sig2 << ' ' << sum2 << ' ' << minc2 << '\n';
    if (sig1) {
        dp[cur][2]=min(sum1,dp[cur][2]);
        dp[cur][1]=min(sum1+minc1,dp[cur][1]);
    }
    else {
        dp[cur][1]=min(sum1,dp[cur][1]);
        dp[cur][2]=min(sum1+minc1,dp[cur][2]);
    }
    if (sig2) {
        dp[cur][0]=min(sum2,dp[cur][0]);
        dp[cur][3]=min(sum2+minc2,dp[cur][3]);
    }
    else {
        dp[cur][3]=min(sum2,dp[cur][3]);
        dp[cur][0]=min(sum2+minc2,dp[cur][0]);
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin >> n;
    int a,b;
    for (int i=0; i<n-1; i++) {
        cin >> a >> b;
        graph[--a].pb(--b);
        graph[b].pb(a);
    }
    for (int i=0; i<n; i++) {
        cin >> onoff[i];
    }
    dfs(0);
    int ans=min(dp[0][0]+1,dp[0][1]);
    if (ans>=1e9) {
        cout << "impossible\n";
    }
    else {
        cout << ans << '\n';
    }
    /*for (int i=0; i<n; i++) {
        cout << "i: " << i+1 << " - ";
        for (int j=0; j<4; j++) {
            cout << dp[i][j] << ' ';
        }
        cout << '\n';
    }*/
    return 0;
}

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 8536 KB Output is correct
2 Correct 6 ms 8540 KB Output is correct
3 Correct 6 ms 8540 KB Output is correct
4 Correct 6 ms 8536 KB Output is correct
5 Correct 6 ms 8572 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 8536 KB Output is correct
2 Correct 6 ms 8540 KB Output is correct
3 Correct 6 ms 8540 KB Output is correct
4 Correct 6 ms 8536 KB Output is correct
5 Correct 6 ms 8572 KB Output is correct
6 Correct 6 ms 8540 KB Output is correct
7 Correct 6 ms 8540 KB Output is correct
8 Correct 7 ms 8540 KB Output is correct
9 Correct 8 ms 8796 KB Output is correct
10 Correct 7 ms 8536 KB Output is correct
11 Correct 6 ms 8540 KB Output is correct
12 Correct 6 ms 8540 KB Output is correct
13 Correct 6 ms 8536 KB Output is correct
14 Correct 6 ms 8540 KB Output is correct
15 Correct 8 ms 8540 KB Output is correct
16 Correct 6 ms 8536 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 45 ms 21068 KB Output is correct
2 Correct 39 ms 22208 KB Output is correct
3 Correct 41 ms 22540 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 41 ms 21076 KB Output is correct
2 Correct 39 ms 22040 KB Output is correct
3 Correct 48 ms 22356 KB Output is correct
4 Correct 36 ms 12684 KB Output is correct
5 Correct 43 ms 13056 KB Output is correct
6 Correct 49 ms 13148 KB Output is correct
7 Correct 6 ms 8536 KB Output is correct
8 Correct 16 ms 10072 KB Output is correct
9 Correct 40 ms 13136 KB Output is correct
10 Correct 47 ms 13136 KB Output is correct
11 Correct 56 ms 13692 KB Output is correct
12 Correct 42 ms 13776 KB Output is correct
13 Correct 45 ms 12636 KB Output is correct
14 Correct 40 ms 13144 KB Output is correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 8536 KB Output is correct
2 Correct 6 ms 8540 KB Output is correct
3 Correct 6 ms 8540 KB Output is correct
4 Correct 6 ms 8536 KB Output is correct
5 Correct 6 ms 8572 KB Output is correct
6 Correct 6 ms 8540 KB Output is correct
7 Correct 6 ms 8540 KB Output is correct
8 Correct 7 ms 8540 KB Output is correct
9 Correct 8 ms 8796 KB Output is correct
10 Correct 7 ms 8536 KB Output is correct
11 Correct 6 ms 8540 KB Output is correct
12 Correct 6 ms 8540 KB Output is correct
13 Correct 6 ms 8536 KB Output is correct
14 Correct 6 ms 8540 KB Output is correct
15 Correct 8 ms 8540 KB Output is correct
16 Correct 6 ms 8536 KB Output is correct
17 Correct 45 ms 21068 KB Output is correct
18 Correct 39 ms 22208 KB Output is correct
19 Correct 41 ms 22540 KB Output is correct
20 Correct 41 ms 21076 KB Output is correct
21 Correct 39 ms 22040 KB Output is correct
22 Correct 48 ms 22356 KB Output is correct
23 Correct 36 ms 12684 KB Output is correct
24 Correct 43 ms 13056 KB Output is correct
25 Correct 49 ms 13148 KB Output is correct
26 Correct 6 ms 8536 KB Output is correct
27 Correct 16 ms 10072 KB Output is correct
28 Correct 40 ms 13136 KB Output is correct
29 Correct 47 ms 13136 KB Output is correct
30 Correct 56 ms 13692 KB Output is correct
31 Correct 42 ms 13776 KB Output is correct
32 Correct 45 ms 12636 KB Output is correct
33 Correct 40 ms 13144 KB Output is correct
34 Correct 6 ms 8540 KB Output is correct
35 Correct 6 ms 8540 KB Output is correct
36 Correct 6 ms 8536 KB Output is correct
37 Correct 7 ms 8540 KB Output is correct
38 Correct 6 ms 8532 KB Output is correct
39 Correct 8 ms 8540 KB Output is correct
40 Correct 6 ms 8536 KB Output is correct
41 Correct 6 ms 8540 KB Output is correct
42 Correct 6 ms 8556 KB Output is correct
43 Correct 6 ms 8540 KB Output is correct
44 Correct 6 ms 8540 KB Output is correct
45 Correct 41 ms 22244 KB Output is correct
46 Correct 39 ms 22096 KB Output is correct
47 Correct 42 ms 22448 KB Output is correct
48 Correct 50 ms 12452 KB Output is correct
49 Correct 39 ms 12880 KB Output is correct
50 Correct 40 ms 13164 KB Output is correct
51 Correct 6 ms 8540 KB Output is correct
52 Correct 16 ms 10136 KB Output is correct
53 Correct 41 ms 13136 KB Output is correct
54 Correct 46 ms 13220 KB Output is correct
55 Correct 45 ms 13648 KB Output is correct
56 Correct 48 ms 13900 KB Output is correct
57 Correct 35 ms 13124 KB Output is correct
58 Correct 43 ms 12936 KB Output is correct
59 Correct 19 ms 10072 KB Output is correct
60 Correct 60 ms 12884 KB Output is correct
61 Correct 42 ms 13136 KB Output is correct
62 Correct 38 ms 13144 KB Output is correct
63 Correct 41 ms 13140 KB Output is correct
64 Correct 46 ms 13136 KB Output is correct
65 Correct 34 ms 13660 KB Output is correct
66 Correct 43 ms 13560 KB Output is correct
67 Correct 35 ms 13512 KB Output is correct
68 Correct 40 ms 13320 KB Output is correct
69 Correct 45 ms 13524 KB Output is correct
70 Correct 32 ms 13404 KB Output is correct