Init

ACMOJ-2057.cpp

@@ -0,0 +1,66 @@
+#include <algorithm>
+#include <cstdio>
+#include <cstring>
+using namespace std;
+typedef long long LL;
+const int kMaxn = 1e5 + 10;
+const int kMaxv = 1e5;
+int n, m;
+int a[kMaxn], max_d[kMaxn], min_d[kMaxn];
+int f[kMaxn], res, pos[kMaxn];
+bool cmp_max_d(int a, int b) { return max_d[a] < max_d[b]; }
+bool cmp_a(int x, int y) { return a[x] < a[y]; }
+int val[kMaxn];
+void Modify(int p, int v) {
+  for (; p <= kMaxv; p += p & (-p)) val[p] = max(val[p], v);
+}
+int Query(int p) {
+  int res = 0;
+  for (; p > 0; p -= p & (-p)) res = max(res, val[p]);
+  return res;
+}
+void Clear(int p) {
+  for (; p <= kMaxv; p += p & (-p)) val[p] = 0;
+}
+void CDQ(int L, int R) {
+  if (L == R) {
+    f[L] = max(f[L], 1);
+    return;
+  }
+  int M = (L + R) >> 1;
+  CDQ(L, M);
+  for (int i = L; i <= R; i++) pos[i] = i;
+  sort(pos + L, pos + M + 1, cmp_max_d);
+  sort(pos + M + 1, pos + R + 1, cmp_a);
+  int pl = L;
+  for (int pr = M + 1; pr <= R; pr++) {
+    while (pl <= M && max_d[pos[pl]] <= a[pos[pr]]) {
+      Modify(a[pos[pl]], f[pos[pl]]);
+      pl++;
+    }
+    f[pos[pr]] = max(f[pos[pr]], Query(min_d[pos[pr]]) + 1);
+  }
+  for (int i = L; i <= M; i++) Clear(a[i]);
+  CDQ(M + 1, R);
+}
+int main() {
+#ifdef local
+  freopen("pro.in", "r", stdin);
+#endif
+  scanf("%d%d", &n, &m);
+  for (int i = 1; i <= n; i++) {
+    scanf("%d", &a[i]);
+    max_d[i] = a[i];
+    min_d[i] = a[i];
+  }
+  for (int i = 1; i <= m; i++) {
+    int x, y;
+    scanf("%d%d", &x, &y);
+    max_d[x] = max(max_d[x], y);
+    min_d[x] = min(min_d[x], y);
+  }
+  CDQ(1, n);
+  for (int i = 1; i <= n; i++) res = max(res, f[i]);
+  printf("%d\n", res);
+  return 0;
+}