#include <stdio.h>
#include <stdlib.h>
#define N 1000
#define INF 0x3f3f3f3f
int min(int a, int b) { return a < b ? a : b; }
int *ej[N], eo[N], dd[N];
void append(int i, int j) {
int o = eo[i]++;
if (o >= 2 && (o & o - 1) == 0)
ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
ej[i][o] = j;
}
int dp[N][2][2];
void dfs(int i) {
int o, c, d;
if (dd[i] == eo[i] - 1) {
dd[i] = -1;
for (o = eo[i]; o--; ) {
int j = ej[i][o];
if (dd[j] != -1) {
for (c = 0; c < 2; c++)
for (d = 1; d >= 0; d--) {
int x = INF;
if (dp[i][0][1 - c] != INF)
x = min(x, dp[j][c][d] + dp[i][0][1 - c]);
if (d == 1 && dp[i][1][1 - c] != INF)
x = min(x, dp[j][c][0] + dp[i][1][1 - c]);
dp[j][c][d] = x;
}
dd[j]++, dfs(j);
break;
}
}
}
}
int main() {
static int qu[N], dp_[2][2][2][2], dq_[2][2][2][2];
int n, h, i, j, o, cnt, c1, d1, c2, d2, c3, d3, ans;
scanf("%d", &n);
if (n > N) {
printf("%d\n", n % 4 == 0 ? n / 2 : -1);
return 0;
}
for (i = 0; i < n; i++)
ej[i] = (int *) malloc(2 * sizeof *ej[i]);
for (h = 0; h < n; h++) {
scanf("%d%d", &i, &j), i--, j--;
append(i, j), append(j, i);
}
for (i = 0; i < n; i++)
dp[i][0][0] = 0, dp[i][0][1] = INF, dp[i][1][0] = 1, dp[i][1][1] = INF;
for (i = 0; i < n; i++)
dfs(i);
for (i = 0; i < n; i++)
if (dd[i] != -1)
break;
cnt = 0;
while (dd[i] != -1) {
dd[i] = -1, qu[cnt++] = i;
for (o = eo[i]; o--; ) {
j = ej[i][o];
if (dd[j] != -1) {
i = j;
break;
}
}
}
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++)
dp_[c1][d1][c2][d2] = INF;
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++) {
if (d1 + c2 > 1 || d2 + c1 > 1)
continue;
dp_[c1][d1 + c2][c2][d2 + c1] = min(dp_[c1][d1 + c2][c2][d2 + c1], dp[qu[0]][c1][d1] + dp[qu[1]][c2][d2]);
}
for (h = 2; h < cnt; h++) {
i = qu[h];
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++)
dq_[c1][d1][c2][d2] = INF;
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++) {
int x = dp_[c1][d1][c2][d2];
if (x == INF)
continue;
for (c3 = 0; c3 < 2; c3++)
for (d3 = 0; d3 < 2; d3++) {
int y = dp[i][c3][d3];
if (d2 + c3 != 1 || d3 + c2 > 1 || y == INF)
continue;
dq_[c1][d1][c3][d3 + c2] = min(dq_[c1][d1][c3][d3 + c2], x + y);
}
}
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++)
dp_[c1][d1][c2][d2] = dq_[c1][d1][c2][d2];
}
ans = INF;
for (c1 = 0; c1 < 2; c1++)
for (d1 = 0; d1 < 2; d1++)
for (c2 = 0; c2 < 2; c2++)
for (d2 = 0; d2 < 2; d2++)
if (d1 + c2 == 1 && d2 + c1 == 1)
ans = min(ans, dp_[c1][d1][c2][d2]);
if (ans == INF)
ans = -1;
printf("%d\n", ans);
return 0;
}
Compilation message
Main.c: In function 'append':
Main.c:14:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
14 | if (o >= 2 && (o & o - 1) == 0)
| ~~^~~
Main.c: In function 'main':
Main.c:51:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
51 | scanf("%d", &n);
| ^~~~~~~~~~~~~~~
Main.c:59:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
59 | scanf("%d%d", &i, &j), i--, j--;
| ^~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
204 KB |
Output is correct |
11 |
Correct |
0 ms |
204 KB |
Output is correct |
12 |
Correct |
0 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
204 KB |
Output is correct |
11 |
Correct |
0 ms |
204 KB |
Output is correct |
12 |
Correct |
0 ms |
204 KB |
Output is correct |
13 |
Correct |
1 ms |
332 KB |
Output is correct |
14 |
Correct |
0 ms |
336 KB |
Output is correct |
15 |
Correct |
1 ms |
336 KB |
Output is correct |
16 |
Correct |
1 ms |
288 KB |
Output is correct |
17 |
Correct |
0 ms |
208 KB |
Output is correct |
18 |
Correct |
0 ms |
336 KB |
Output is correct |
19 |
Correct |
0 ms |
208 KB |
Output is correct |
20 |
Correct |
0 ms |
336 KB |
Output is correct |
21 |
Correct |
1 ms |
336 KB |
Output is correct |
22 |
Correct |
0 ms |
336 KB |
Output is correct |
23 |
Correct |
1 ms |
288 KB |
Output is correct |
24 |
Correct |
1 ms |
336 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
204 KB |
Output is correct |
11 |
Correct |
0 ms |
204 KB |
Output is correct |
12 |
Correct |
0 ms |
204 KB |
Output is correct |
13 |
Correct |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
0 ms |
204 KB |
Output is correct |
15 |
Correct |
0 ms |
204 KB |
Output is correct |
16 |
Correct |
0 ms |
204 KB |
Output is correct |
17 |
Correct |
0 ms |
204 KB |
Output is correct |
18 |
Correct |
0 ms |
204 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
0 ms |
204 KB |
Output is correct |
21 |
Correct |
1 ms |
332 KB |
Output is correct |
22 |
Correct |
0 ms |
336 KB |
Output is correct |
23 |
Correct |
1 ms |
336 KB |
Output is correct |
24 |
Correct |
1 ms |
288 KB |
Output is correct |
25 |
Correct |
0 ms |
208 KB |
Output is correct |
26 |
Correct |
0 ms |
336 KB |
Output is correct |
27 |
Correct |
0 ms |
208 KB |
Output is correct |
28 |
Correct |
0 ms |
336 KB |
Output is correct |
29 |
Correct |
1 ms |
336 KB |
Output is correct |
30 |
Correct |
0 ms |
336 KB |
Output is correct |
31 |
Correct |
1 ms |
288 KB |
Output is correct |
32 |
Correct |
1 ms |
336 KB |
Output is correct |
33 |
Incorrect |
0 ms |
336 KB |
Output isn't correct |
34 |
Halted |
0 ms |
0 KB |
- |