#include <bits/stdc++.h>
using namespace std;
int n, p[100002], node1, node2;
vector<int>G[100002];
int preset[100002];
long long dp[100002][2][2];
int find (int x) {
if (p[x] == x)
return x;
return p[x] = find(p[x]);
}
void dfs (int nod, int par) {
vector<int>sons;
for (auto it : G[nod])
if (it != par) {
sons.push_back(it);
dfs(it, nod);
}
for (int cul = 0; cul < 2; cul++)
for (int cul2 = 0; cul2 < 2; cul2++) {
if (cul2 && nod == 1)
continue;
if (preset[nod] != -1 && preset[nod] != cul)
continue;
int blue = (cul2 + (preset[nod] != -1 && preset[node1 + node2 - nod] == 1));
if (blue == 2 && par == node1 + node2 - nod)
blue--;
if (blue == 2)
continue;
dp[nod][cul][cul2] = 0;
for (auto it : sons)
dp[nod][cul][cul2] += dp[it][0][cul];
if (!blue) {
long long add = -1e9;
for (auto it : sons)
add = max(add, dp[it][1][cul] - dp[it][0][cul]);
dp[nod][cul][cul2] += add;
}
dp[nod][cul][cul2] += (!cul);
}
}
void reset() {
for (int k = 1; k <= n; k++)
for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++)
dp[k][i][j] = -1e9;
}
int main ()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 1; i <= n; i++)
p[i] = i;
for (int i = 1; i <= n; i++) {
int x, y;
cin >> x >> y;
if (find(x) == find(y))
node1 = x, node2 = y;
else {
G[x].push_back(y);
G[y].push_back(x);
}
p[find(x)] = find(y);
}
memset(preset, -1, sizeof(preset));
long long ans = 1e18;
for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++) {
reset();
preset[node1] = i;
preset[node2] = j;
dfs(1, 0);
ans = min(ans, n - max(dp[1][0][0], dp[1][1][0]));
}
cout << (ans >= n ? -1 : ans);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
3028 KB |
Output is correct |
2 |
Correct |
2 ms |
3028 KB |
Output is correct |
3 |
Correct |
1 ms |
3028 KB |
Output is correct |
4 |
Correct |
1 ms |
3028 KB |
Output is correct |
5 |
Correct |
131 ms |
26896 KB |
Output is correct |
6 |
Correct |
150 ms |
26444 KB |
Output is correct |
7 |
Correct |
133 ms |
22152 KB |
Output is correct |
8 |
Correct |
125 ms |
23236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
3028 KB |
Output is correct |
2 |
Correct |
2 ms |
3028 KB |
Output is correct |
3 |
Correct |
2 ms |
3028 KB |
Output is correct |
4 |
Correct |
2 ms |
3028 KB |
Output is correct |
5 |
Correct |
2 ms |
3064 KB |
Output is correct |
6 |
Correct |
2 ms |
3036 KB |
Output is correct |
7 |
Correct |
2 ms |
3064 KB |
Output is correct |
8 |
Correct |
2 ms |
3028 KB |
Output is correct |
9 |
Correct |
2 ms |
3028 KB |
Output is correct |
10 |
Correct |
2 ms |
3028 KB |
Output is correct |
11 |
Correct |
2 ms |
3028 KB |
Output is correct |
12 |
Correct |
2 ms |
3028 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
3028 KB |
Output is correct |
2 |
Correct |
2 ms |
3028 KB |
Output is correct |
3 |
Correct |
2 ms |
3028 KB |
Output is correct |
4 |
Correct |
2 ms |
3028 KB |
Output is correct |
5 |
Correct |
2 ms |
3064 KB |
Output is correct |
6 |
Correct |
2 ms |
3036 KB |
Output is correct |
7 |
Correct |
2 ms |
3064 KB |
Output is correct |
8 |
Correct |
2 ms |
3028 KB |
Output is correct |
9 |
Correct |
2 ms |
3028 KB |
Output is correct |
10 |
Correct |
2 ms |
3028 KB |
Output is correct |
11 |
Correct |
2 ms |
3028 KB |
Output is correct |
12 |
Correct |
2 ms |
3028 KB |
Output is correct |
13 |
Correct |
2 ms |
3028 KB |
Output is correct |
14 |
Correct |
2 ms |
3028 KB |
Output is correct |
15 |
Correct |
2 ms |
3056 KB |
Output is correct |
16 |
Correct |
3 ms |
3028 KB |
Output is correct |
17 |
Correct |
2 ms |
3028 KB |
Output is correct |
18 |
Correct |
3 ms |
3072 KB |
Output is correct |
19 |
Correct |
2 ms |
3028 KB |
Output is correct |
20 |
Correct |
2 ms |
3028 KB |
Output is correct |
21 |
Correct |
2 ms |
3064 KB |
Output is correct |
22 |
Correct |
2 ms |
3156 KB |
Output is correct |
23 |
Correct |
2 ms |
3156 KB |
Output is correct |
24 |
Correct |
2 ms |
3156 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
3028 KB |
Output is correct |
2 |
Correct |
2 ms |
3028 KB |
Output is correct |
3 |
Correct |
1 ms |
3028 KB |
Output is correct |
4 |
Correct |
1 ms |
3028 KB |
Output is correct |
5 |
Correct |
131 ms |
26896 KB |
Output is correct |
6 |
Correct |
150 ms |
26444 KB |
Output is correct |
7 |
Correct |
133 ms |
22152 KB |
Output is correct |
8 |
Correct |
125 ms |
23236 KB |
Output is correct |
9 |
Correct |
2 ms |
3028 KB |
Output is correct |
10 |
Correct |
2 ms |
3028 KB |
Output is correct |
11 |
Correct |
2 ms |
3028 KB |
Output is correct |
12 |
Correct |
2 ms |
3028 KB |
Output is correct |
13 |
Correct |
2 ms |
3064 KB |
Output is correct |
14 |
Correct |
2 ms |
3036 KB |
Output is correct |
15 |
Correct |
2 ms |
3064 KB |
Output is correct |
16 |
Correct |
2 ms |
3028 KB |
Output is correct |
17 |
Correct |
2 ms |
3028 KB |
Output is correct |
18 |
Correct |
2 ms |
3028 KB |
Output is correct |
19 |
Correct |
2 ms |
3028 KB |
Output is correct |
20 |
Correct |
2 ms |
3028 KB |
Output is correct |
21 |
Correct |
2 ms |
3028 KB |
Output is correct |
22 |
Correct |
2 ms |
3028 KB |
Output is correct |
23 |
Correct |
2 ms |
3056 KB |
Output is correct |
24 |
Correct |
3 ms |
3028 KB |
Output is correct |
25 |
Correct |
2 ms |
3028 KB |
Output is correct |
26 |
Correct |
3 ms |
3072 KB |
Output is correct |
27 |
Correct |
2 ms |
3028 KB |
Output is correct |
28 |
Correct |
2 ms |
3028 KB |
Output is correct |
29 |
Correct |
2 ms |
3064 KB |
Output is correct |
30 |
Correct |
2 ms |
3156 KB |
Output is correct |
31 |
Correct |
2 ms |
3156 KB |
Output is correct |
32 |
Correct |
2 ms |
3156 KB |
Output is correct |
33 |
Correct |
122 ms |
9980 KB |
Output is correct |
34 |
Correct |
87 ms |
10096 KB |
Output is correct |
35 |
Correct |
90 ms |
10100 KB |
Output is correct |
36 |
Correct |
81 ms |
10096 KB |
Output is correct |
37 |
Correct |
17 ms |
4724 KB |
Output is correct |
38 |
Correct |
80 ms |
10076 KB |
Output is correct |
39 |
Correct |
8 ms |
3668 KB |
Output is correct |
40 |
Correct |
119 ms |
9936 KB |
Output is correct |
41 |
Correct |
47 ms |
12320 KB |
Output is correct |
42 |
Correct |
51 ms |
11752 KB |
Output is correct |
43 |
Correct |
131 ms |
23352 KB |
Output is correct |
44 |
Correct |
106 ms |
20340 KB |
Output is correct |