Create nocross.cpp

1 files changed, 57 insertions, 0 deletions

diff --git a/2017/February/Platinum/nocross.cpp b/2017/February/Platinum/nocross.cpp
new file mode 100644
index 0000000..5ce1b7c
--- /dev/null
+++ b/2017/February/Platinum/nocross.cpp
@@ -0,0 +1,57 @@
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <queue>
+#include <set>
+#include <map>
+#include <unordered_set>
+#include <unordered_map>
+#include <cmath>
+#include <cstring>
+using namespace std;
+typedef long long ll;
+typedef pair<int, int> ii;
+typedef vector<int> vi;
+typedef vector<ii> vii;
+constexpr auto INF = (int)1e9;
+constexpr auto MAXN = 100005;
+
+int N, A[100005], B[100005], R[100005], seg[4 * MAXN] = { 0 };
+
+void update(int x, int v, int l = 0, int r = -1, int n = 1) {
+	if (r == -1) r = N - 1;
+	if (l == r) seg[n] = max(v, seg[n]);
+	else {
+		int m = (l + r) >> 1;
+		x <= m ? update(x, v, l, m, n << 1) : update(x, v, m + 1, r, n << 1 | 1);
+		seg[n] = max(seg[n << 1], seg[n << 1 | 1]);
+	}
+}
+
+int query(int a, int b, int l = 0, int r = -1, int n = 1) {
+	if (r == -1) r = N - 1;
+	if (l > b || r < a) return 0;
+	if (l >= a && r <= b) return seg[n];
+	int m = (l + r) >> 1;
+	return max(query(a, b, l, m, n << 1), query(a, b, m + 1, r, n << 1 | 1));
+}
+
+int main() {
+	ifstream cin("nocross.in");
+	ofstream cout("nocross.out");
+
+	cin >> N;
+	for (int i = 0; i < N; ++i) cin >> A[i], A[i]--;
+	for (int i = 0; i < N; ++i) cin >> B[i], B[i]--;
+	for (int i = 0; i < N; ++i) R[B[i]] = i;
+
+	for (int i = 0; i < N; ++i) {
+		vii u;
+		for (int j = max(A[i] - 4, 0); j < min(A[i] + 5, N); ++j) u.emplace_back(R[j], query(0, R[j] - 1) + 1);
+		for (auto q : u) update(q.first, q.second);
+	}
+
+	cout << query(0, N - 1) << endl;
+}