Submission #545938

#TimeUsernameProblemLanguageResultExecution timeMemory
545938rainboySpring cleaning (CEOI20_cleaning)C11
100 / 100
111 ms16164 KiB
#include <stdio.h> #include <string.h> #include <stdlib.h> #define N 100000 unsigned int X = 12345; int rand_() { return (X *= 3) >> 1; } int *ej[N], eo[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 dd[N], pp[N], qq[N], sz[N], ta[N], dp[N]; void dfs1(int p, int i, int d) { static int time; int o, j_; dd[i] = d, pp[i] = p, ta[i] = time++; dp[i] = eo[i] == 1; j_ = -1, sz[i] = 1; for (o = eo[i]; o--; ) { int j = ej[i][o]; if (j != p) { dfs1(i, j, d + 1); if (j_ == -1 || sz[j_] < sz[j]) j_ = j; sz[i] += sz[j]; dp[i] += dp[j]; } } if (j_ != -1) qq[j_] = -1; } int ans; void dfs2(int p, int i) { int o; if (p != -1) { ans += dp[i] % 2 == 0 ? 2 : 1; dp[i] = dp[p] + (dp[i] % 2 == 0 ? -1 : 1); } else dp[i] = 0; qq[i] = qq[i] ? qq[pp[i]] : i; for (o = eo[i]; o--; ) { int j = ej[i][o]; if (j != p) dfs2(i, j); } } int lca(int i, int j) { while (qq[i] != qq[j]) if (dd[qq[i]] > dd[qq[j]]) i = pp[qq[i]]; else j = pp[qq[j]]; return dd[i] < dd[j] ? i : j; } void sort(int *ii, int l, int r) { while (l < r) { int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp; while (j < k) if (ii[j] == i_) j++; else if (ta[ii[j]] < ta[i_]) { tmp = ii[i], ii[i] = ii[j], ii[j] = tmp; i++, j++; } else { k--; tmp = ii[j], ii[j] = ii[k], ii[k] = tmp; } sort(ii, l, i); l = k; } } int main() { int n, q, h, i, j, l, r; scanf("%d%d", &n, &q); for (i = 0; i < n; i++) ej[i] = (int *) malloc(2 * sizeof *ej[i]); for (h = 0; h < n - 1; h++) { scanf("%d%d", &i, &j), i--, j--; append(i, j), append(j, i); } l = 0, r = -1; for (i = 0; i < n; i++) if (eo[i] == 1) l++; else r = i; dfs1(-1, r, 0); dfs2(-1, r); while (q--) { static int kk[N], ii[N], qu[N]; int k, k_, h, cnt, ans_; scanf("%d", &k); for (h = 0; h < k; h++) { scanf("%d", &ii[h]), ii[h]--; kk[ii[h]]++; } ans_ = ans + k; k_ = 0; for (h = 0; h < k; h++) { if (kk[ii[h]] && (kk[ii[h]] - (eo[ii[h]] == 1 ? 1 : 0)) % 2 != 0) ii[k_++] = ii[h]; kk[ii[h]] = 0; } k = k_; if ((l + k) % 2 != 0) { printf("-1\n"); continue; } sort(ii, 0, k); if (k != 0) { cnt = 0; if (r != ii[0]) qu[cnt++] = r, qu[cnt++] = ii[0]; for (h = 1; h <= k; h++) { int a = h == k ? r : lca(ii[h - 1], ii[h]), flip; flip = 1; while (cnt >= 2 && dd[qu[cnt - 2]] >= dd[a]) { if (flip) ans_ += dp[qu[cnt - 1]] - dp[qu[cnt - 2]]; flip ^= 1; cnt--; } if (cnt > 0) { if (flip) ans_ += dp[qu[cnt - 1]] - dp[a], qu[cnt - 1] = a; else cnt--; qu[cnt++] = ii[h]; } else qu[cnt++] = a, qu[cnt++] = ii[h]; } } printf("%d\n", ans_); } return 0; }

Compilation message (stderr)

cleaning.c: In function 'append':
cleaning.c:18:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   18 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
cleaning.c: In function 'main':
cleaning.c:97:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |  scanf("%d%d", &n, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~
cleaning.c:101:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~
cleaning.c:116:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |   scanf("%d", &k);
      |   ^~~~~~~~~~~~~~~
cleaning.c:118:4: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |    scanf("%d", &ii[h]), ii[h]--;
      |    ^~~~~~~~~~~~~~~~~~~
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