oj.uz

Submission #489340

# Submission time Handle Problem Language Result Execution time Memory
489340 2021-11-22T14:49:03 Z cpp219 The Xana coup (BOI21_xanadu) C++14
100 / 100
 92 ms 13864 KB 
#include<bits/stdc++.h>
#define ll int
#define ld long double
#define fs first
#define sc second
#define debug(y) cout<<y,exit(0)
using namespace std;
typedef pair<ll,ll> LL;
const ll N = 1e5 + 9;
const ll inf = 1e9 + 7;

vector<ll> g[N];
ll n,x,y,a[N],dp[N][4];

bool chk(ll x,ll i){
    return (x >> i) & 1;
}

void Combine(ll u,ll v){
    ll tmp[4]; tmp[0] = tmp[1] = tmp[2] = tmp[3] = inf;
    for (ll i = 0;i < 4;i++)
        for (ll j = 0;j < 4;j++){
            if (chk(i,0) && !chk(j,1)) continue;
            if (!chk(i,0) && chk(j,1)) continue;
            ll now = chk(i,1) ^ chk(j,0); now = now*2 + chk(i,0);
            tmp[now] = min(tmp[now],dp[u][i] + dp[v][j]);
        }
    for (ll i = 0;i < 4;i++) dp[u][i] = tmp[i];
}

void DFS(ll u,ll p){
    dp[u][a[u]*2] = 0; dp[u][(1^a[u])*2 + 1] = 1;
    for (auto i : g[u]) if (i != p){
        DFS(i,u); Combine(u,i);
    }
}

int main(){
    ios_base::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
    #define task "tst"
    if (fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        //freopen(task".out","w",stdout);
    }
    cin>>n;
    for (ll i = 1;i < n;i++){
        cin>>x>>y;
        g[x].push_back(y); g[y].push_back(x);
    }
    for (ll i = 1;i <= n;i++){
        cin>>a[i];
        for (ll j = 0;j < 4;j++) dp[i][j] = inf;
    }
    DFS(1,0);
    ll kq = min(dp[1][0],dp[1][1]);
    if (kq == inf) cout<<"impossible";
    else cout<<kq;
}

/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/

Compilation message

xanadu.cpp: In function 'int main()':
xanadu.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2636 KB Output is correct
2 Correct 2 ms 2784 KB Output is correct
3 Correct 2 ms 2680 KB Output is correct
4 Correct 1 ms 2640 KB Output is correct
5 Correct 1 ms 2640 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2636 KB Output is correct
2 Correct 2 ms 2784 KB Output is correct
3 Correct 2 ms 2680 KB Output is correct
4 Correct 1 ms 2640 KB Output is correct
5 Correct 1 ms 2640 KB Output is correct
6 Correct 2 ms 2592 KB Output is correct
7 Correct 2 ms 2640 KB Output is correct
8 Correct 2 ms 2640 KB Output is correct
9 Correct 2 ms 2640 KB Output is correct
10 Correct 3 ms 2640 KB Output is correct
11 Correct 1 ms 2640 KB Output is correct
12 Correct 2 ms 2676 KB Output is correct
13 Correct 2 ms 2640 KB Output is correct
14 Correct 2 ms 2640 KB Output is correct
15 Correct 1 ms 2640 KB Output is correct
16 Correct 1 ms 2600 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 13628 KB Output is correct
2 Correct 64 ms 13560 KB Output is correct
3 Correct 52 ms 13692 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 65 ms 13712 KB Output is correct
2 Correct 46 ms 13508 KB Output is correct
3 Correct 63 ms 13864 KB Output is correct
4 Correct 47 ms 8312 KB Output is correct
5 Correct 61 ms 8876 KB Output is correct
6 Correct 70 ms 8980 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 14 ms 4832 KB Output is correct
9 Correct 66 ms 9012 KB Output is correct
10 Correct 62 ms 9100 KB Output is correct
11 Correct 62 ms 9304 KB Output is correct
12 Correct 92 ms 9488 KB Output is correct
13 Correct 86 ms 8656 KB Output is correct
14 Correct 84 ms 9088 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2636 KB Output is correct
2 Correct 2 ms 2784 KB Output is correct
3 Correct 2 ms 2680 KB Output is correct
4 Correct 1 ms 2640 KB Output is correct
5 Correct 1 ms 2640 KB Output is correct
6 Correct 2 ms 2592 KB Output is correct
7 Correct 2 ms 2640 KB Output is correct
8 Correct 2 ms 2640 KB Output is correct
9 Correct 2 ms 2640 KB Output is correct
10 Correct 3 ms 2640 KB Output is correct
11 Correct 1 ms 2640 KB Output is correct
12 Correct 2 ms 2676 KB Output is correct
13 Correct 2 ms 2640 KB Output is correct
14 Correct 2 ms 2640 KB Output is correct
15 Correct 1 ms 2640 KB Output is correct
16 Correct 1 ms 2600 KB Output is correct
17 Correct 46 ms 13628 KB Output is correct
18 Correct 64 ms 13560 KB Output is correct
19 Correct 52 ms 13692 KB Output is correct
20 Correct 65 ms 13712 KB Output is correct
21 Correct 46 ms 13508 KB Output is correct
22 Correct 63 ms 13864 KB Output is correct
23 Correct 47 ms 8312 KB Output is correct
24 Correct 61 ms 8876 KB Output is correct
25 Correct 70 ms 8980 KB Output is correct
26 Correct 2 ms 2636 KB Output is correct
27 Correct 14 ms 4832 KB Output is correct
28 Correct 66 ms 9012 KB Output is correct
29 Correct 62 ms 9100 KB Output is correct
30 Correct 62 ms 9304 KB Output is correct
31 Correct 92 ms 9488 KB Output is correct
32 Correct 86 ms 8656 KB Output is correct
33 Correct 84 ms 9088 KB Output is correct
34 Correct 1 ms 2640 KB Output is correct
35 Correct 2 ms 2640 KB Output is correct
36 Correct 2 ms 2660 KB Output is correct
37 Correct 2 ms 2684 KB Output is correct
38 Correct 2 ms 2640 KB Output is correct
39 Correct 2 ms 2640 KB Output is correct
40 Correct 2 ms 2676 KB Output is correct
41 Correct 2 ms 2640 KB Output is correct
42 Correct 2 ms 2640 KB Output is correct
43 Correct 1 ms 2640 KB Output is correct
44 Correct 2 ms 2640 KB Output is correct
45 Correct 44 ms 13696 KB Output is correct
46 Correct 43 ms 13500 KB Output is correct
47 Correct 69 ms 13696 KB Output is correct
48 Correct 74 ms 8292 KB Output is correct
49 Correct 55 ms 8960 KB Output is correct
50 Correct 59 ms 9052 KB Output is correct
51 Correct 2 ms 2640 KB Output is correct
52 Correct 15 ms 4748 KB Output is correct
53 Correct 70 ms 9032 KB Output is correct
54 Correct 49 ms 9032 KB Output is correct
55 Correct 47 ms 9296 KB Output is correct
56 Correct 51 ms 9484 KB Output is correct
57 Correct 48 ms 8620 KB Output is correct
58 Correct 60 ms 9036 KB Output is correct
59 Correct 14 ms 4776 KB Output is correct
60 Correct 44 ms 8452 KB Output is correct
61 Correct 57 ms 8988 KB Output is correct
62 Correct 54 ms 9084 KB Output is correct
63 Correct 49 ms 9160 KB Output is correct
64 Correct 60 ms 9072 KB Output is correct
65 Correct 50 ms 9640 KB Output is correct
66 Correct 64 ms 9636 KB Output is correct
67 Correct 60 ms 9424 KB Output is correct
68 Correct 34 ms 9416 KB Output is correct
69 Correct 35 ms 9468 KB Output is correct
70 Correct 35 ms 9416 KB Output is correct