From 2ffcdb65090ddb0f15a86876d91b12bd3caab721 Mon Sep 17 00:00:00 2001
From: Lam Haoyin <root@eatswap.org>
Date: Tue, 8 Mar 2022 17:35:16 +0800
Subject: [PATCH] add: 220308-CN [cpp]

---
 cpp/2203/220308-CN.cpp  | 90 +++++++++++++++++++++++++++++++++++++++++
 cpp/2203/CMakeLists.txt |  2 +-
 2 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 cpp/2203/220308-CN.cpp

diff --git a/cpp/2203/220308-CN.cpp b/cpp/2203/220308-CN.cpp
new file mode 100644
index 0000000..6088573
--- /dev/null
+++ b/cpp/2203/220308-CN.cpp
@@ -0,0 +1,90 @@
+#include <string>
+#include <vector>
+#include <unordered_map>
+#include <iostream>
+
+/**
+ * 2055. Plates Between Candles
+ * There is a long table with a line of plates and candles arranged on top of it. You are given a 0-indexed string s consisting of characters '*' and '|' only, where a '*' represents a plate and a '|' represents a candle.
+ * You are also given a 0-indexed 2D integer array queries where queries[i] = [lefti, righti] denotes the substring s[lefti...righti] (inclusive). For each query, you need to find the number of plates between candles that are in the substring. A plate is considered between candles if there is at least one candle to its left and at least one candle to its right in the substring.
+ * For example, s = "||**||**|*", and a query [3, 8] denotes the substring "*||**|". The number of plates between candles in this substring is 2, as each of the two plates has at least one candle in the substring to its left and right.
+ * Return an integer array answer where answer[i] is the answer to the ith query.
+ */
+
+class Solution {
+private:
+	inline static constexpr int HIGH(int x, int y) {
+		const int r = 32 - __builtin_clz(x ^ y);
+		return ((((x | y) >> r) + 1) << r) - 1;
+	}
+
+	inline static constexpr int MID(int x, int y) {
+		return (x | y) & ~((1 << 31 - __builtin_clz(x ^ y)) - 1);
+	}
+
+	inline static constexpr int LOW(int x, int y) {
+		const int r = 32 - __builtin_clz(x ^ y);
+		return (x | y) >> r << r;
+	}
+
+	inline static constexpr int MSB(int x) {
+		return 31 - __builtin_clz(x);
+	}
+
+	static int dp(int L, int R, const std::string& s, std::vector<std::unordered_map<int, int>>& ans) {
+		if (L == R)
+			return int(s[L] == '*');
+		if (L == (R ^ 1))
+			return ans[1][L >> 1] = (s[L] == '*') + (s[R] == '*');
+
+		if (L == LOW(L, R) && R == HIGH(L, R)) {
+			const int x = 1 + MSB(L ^ R), idx = L >> x;
+			auto& m = ans[x];
+			if (m.count(idx))
+				return m[idx];
+			else
+				return m[idx] = dp(L, L | ((1 << (x - 1)) - 1), s, ans) + dp(L | (1 << (x - 1)), R, s, ans);
+		} else {
+			int M = MID(L, R);
+			return dp(L, M - 1, s, ans) + dp(M, R, s, ans);
+		}
+	}
+
+public:
+	static std::vector<int> platesBetweenCandles(const std::string& s, const std::vector<std::vector<int>>& queries) {
+		int n = s.length();
+		std::vector<std::unordered_map<int, int>> ans(32 - __builtin_clz(n));
+		std::vector<int> ret, positions;
+		ret.reserve(queries.size());
+
+		for (int i = 0; i < n; ++i)
+			if (s[i] == '|')
+				positions.push_back(i);
+
+		if (positions.empty())
+			return std::vector<int>(queries.size());
+
+		for (auto i : queries) {
+			auto begin = std::lower_bound(positions.begin(), positions.end(), i[0]);
+			auto end = std::lower_bound(positions.begin(), positions.end(), i[1]);
+			if (begin == end) {
+				ret.push_back(0);
+				continue;
+			}
+			if (end == positions.end() || *end > i[1])
+				--end;
+			if (begin == positions.end() || *begin >= *end)
+				ret.push_back(0);
+			else
+				ret.push_back(dp(*begin, *end, s, ans));
+		}
+		return ret;
+	}
+};
+
+int main() {
+	auto ret = Solution::platesBetweenCandles("*|*|||", {{0, 0}, {1, 3}});
+	for (int i : ret)
+		std::cout << i << ' ';
+	return 0;
+}
diff --git a/cpp/2203/CMakeLists.txt b/cpp/2203/CMakeLists.txt
index f89f8fc..1b94df8 100644
--- a/cpp/2203/CMakeLists.txt
+++ b/cpp/2203/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220308.cpp)
+ADD_EXECUTABLE(2203 220308-CN.cpp)