Submission #481711

#TimeUsernameProblemLanguageResultExecution timeMemory
481711rainboyMatching (COCI20_matching)C11
58 / 110
117 ms6584 KiB
#include <stdio.h> #include <string.h> #define N 100000 #define M N #define M_ (N * 2) int min(int a, int b) { return a < b ? a : b; } int max(int a, int b) { return a > b ? a : b; } unsigned int X = 12345; int rand_() { return (X *= 3) >> 1; } int xx[N], yy[N]; int ii_[M * 2]; int compare_x(int i, int j) { return xx[i] - xx[j]; } int compare_y(int i, int j) { return yy[i] - yy[j]; } int compare_z(int h1, int h2) { return yy[ii_[h1]] != yy[ii_[h2]] ? yy[ii_[h1]] - yy[ii_[h2]] : yy[ii_[h2 ^ 1]] - yy[ii_[h1 ^ 1]]; } int (*compare)(int, int); 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) { int c = compare(ii[j], i_); if (c == 0) j++; else if (c < 0) { 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 ds[(M + 1) * 2]; int find(int i) { return ds[i] < 0 ? i : (ds[i] = find(ds[i])); } void join(int i, int j) { i = find(i); j = find(j); if (i == j) return; if (ds[i] > ds[j]) ds[i] = j; else { if (ds[i] == ds[j]) ds[i]--; ds[j] = i; } } int zz[1 + N], ll[1 + N], rr[1 + N], hh[1 + N], u_, l_, r_; int node(int h) { static int _ = 1; zz[_] = rand_(); hh[_] = h; return _++; } void split(int u, int h) { int c; if (u == 0) { u_ = l_ = r_ = 0; return; } c = xx[ii_[hh[u] << 1 | 0]] - xx[ii_[h << 1 | 0]]; if (c < 0) { split(rr[u], h); rr[u] = l_, l_ = u; } else if (c > 0) { split(ll[u], h); ll[u] = r_, r_ = u; } else { u_ = u, l_ = ll[u], r_ = rr[u]; ll[u] = rr[u] = 0; } } int merge(int u, int v) { if (u == 0) return v; if (v == 0) return u; if (zz[u] < zz[v]) { rr[u] = merge(rr[u], v); return u; } else { ll[v] = merge(u, ll[v]); return v; } } int tr_higher(int x) { int u = u_, i_ = -1; while (u) if (xx[ii_[hh[u] << 1 | 0]] > x) i_ = hh[u], u = ll[u]; else u = rr[u]; return i_; } int main() { static int ii[N], dd[N], cc[M + 1], hh[M]; int n, m, h, i; scanf("%d", &n); for (i = 0; i < n; i++) scanf("%d%d", &xx[i], &yy[i]); for (i = 0; i < n; i++) ii[i] = i; m = 0; compare = compare_x, sort(ii, 0, n); for (i = 0; i < n; i++) if (i + 1 < n && xx[ii[i]] == xx[ii[i + 1]]) { ii_[m << 1 | 0] = ii[i], ii_[m << 1 | 1] = ii[i + 1], m++; dd[ii[i]]++, dd[ii[i + 1]]++; } compare = compare_y, sort(ii, 0, n); for (i = 0; i < n; i++) if (i + 1 < n && yy[ii[i]] == yy[ii[i + 1]]) { ii_[m << 1 | 0] = ii[i], ii_[m << 1 | 1] = ii[i + 1], m++; dd[ii[i]]++, dd[ii[i + 1]]++; } for (i = 0; i < n; i++) if (dd[i] == 0) { printf("NE\n"); return 0; } for (h = 0; h < m * 2; h++) hh[h] = h; compare = compare_z, sort(hh, 0, m * 2); memset(ds, -1, (m + 1) * 2 * sizeof *ds); for (h = 0; h < m * 2; h++) { int h_ = hh[h]; if (yy[ii_[h_]] < yy[ii_[h_ ^ 1]]) { split(u_, h_ >> 1); u_ = merge(merge(l_, node(h_ >> 1)), r_); } else if (yy[ii_[h_]] > yy[ii_[h_ ^ 1]]) { split(u_, h_ >> 1); u_ = merge(l_, r_); } else if (xx[ii_[h_]] < xx[ii_[h_ ^ 1]]) { int l = xx[ii_[h_]] - 1, r = xx[ii_[h_ ^ 1]], h1 = h_ >> 1, h2; while ((h2 = tr_higher(l)) != -1 && (l = xx[ii_[h2 << 1 | 0]]) <= r) join(h1 << 1 | 0, h2 << 1 | 1), join(h1 << 1 | 1, h2 << 1 | 0); } } for (h = 0; h < m; h++) if (dd[ii_[h << 1 | 0]] == 1 || dd[ii_[h << 1 | 1]] == 1) join(h << 1 | 0, m << 1 | 1), join(h << 1 | 1, m << 1 | 0); for (h = 0; h < m; h++) if (find(h << 1 | 0) == find(h << 1 | 1)) { printf("NE\n"); return 0; } for (h = 0; h <= m; h++) cc[h] = find(h << 1 | 0) < find(h << 1 | 1); if (cc[m]) for (h = 0; h <= m; h++) if (find(h << 1 | 0) == find(m << 1 | 0) || find(h << 1 | 0) == find(m << 1 | 1)) cc[h] ^= 1; printf("DA\n"); for (h = 0; h < m; h++) if (cc[h]) printf("%d %d\n", ii_[h << 1 | 0] + 1, ii_[h << 1 | 1] + 1); return 0; }

Compilation message (stderr)

matching.c: In function 'main':
matching.c:129:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
matching.c:131:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  131 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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