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add: 220308-CN, faster [cpp]

This commit is contained in:
Lam Haoyin 2022-03-08 20:53:53 +08:00
parent 2ffcdb6509
commit 2b5dc5138d
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GPG Key ID: 8C089CB1A2B7544F
1 changed files with 22 additions and 20 deletions
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42
cpp/2203/220308-CN.cpp
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@ -2,6 +2,7 @@
#include <vector> #include <vector>
#include <unordered_map> #include <unordered_map>
#include <iostream> #include <iostream>
#include <functional>
/** /**
* 2055. Plates Between Candles * 2055. Plates Between Candles
@ -31,25 +32,6 @@ private:
return 31 - __builtin_clz(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: public:
static std::vector<int> platesBetweenCandles(const std::string& s, const std::vector<std::vector<int>>& queries) { static std::vector<int> platesBetweenCandles(const std::string& s, const std::vector<std::vector<int>>& queries) {
int n = s.length(); int n = s.length();
@ -64,6 +46,26 @@ public:
if (positions.empty()) if (positions.empty())
return std::vector<int>(queries.size()); return std::vector<int>(queries.size());
std::function<int(int, int)> dp;
dp = [&](int L, int R) {
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)) + dp(L | (1 << (x - 1)), R);
} else {
int M = MID(L, R);
return dp(L, M - 1) + dp(M, R);
}
};
for (auto i : queries) { for (auto i : queries) {
auto begin = std::lower_bound(positions.begin(), positions.end(), i[0]); auto begin = std::lower_bound(positions.begin(), positions.end(), i[0]);
auto end = std::lower_bound(positions.begin(), positions.end(), i[1]); auto end = std::lower_bound(positions.begin(), positions.end(), i[1]);
@ -76,7 +78,7 @@ public:
if (begin == positions.end() || *begin >= *end) if (begin == positions.end() || *begin >= *end)
ret.push_back(0); ret.push_back(0);
else else
ret.push_back(dp(*begin, *end, s, ans)); ret.push_back(dp(*begin, *end));
} }
return ret; return ret;
} }