DP/MaximumRectangle.cpp

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• Last update: 2021-03-21 09:59:09+09:00

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• test/MaximumRectangle.test.cpp

Code

#pragma once
#include <vector>
#include <stack>
#include <algorithm>

template <class T> T MaximumRectangle(const std::vector<T>& a) {
	int n = a.size();
	T result = 0;
	std::stack<int> st;
	std::vector<int> L(n), R(n);
	for (int i = 0; i < n; ++i) {
		while (!st.empty() && a[st.top()] >= a[i]) st.pop();
		L[i] = st.empty() ? 0 : st.top() + 1;
		st.push(i);
	}
	while (!st.empty()) st.pop();
	for (int i = n - 1; i >= 0; --i) {
		while (!st.empty() && a[st.top()] >= a[i]) st.pop();
		R[i] = st.empty() ? n : st.top();
		st.push(i);
	}
	for (int i = 0; i < n; ++i) {
		result = std::max(result, a[i] * (R[i] - L[i]));
	}
	return result;
}

#line 2 "DP/MaximumRectangle.cpp"
#include <vector>
#include <stack>
#include <algorithm>

template <class T> T MaximumRectangle(const std::vector<T>& a) {
	int n = a.size();
	T result = 0;
	std::stack<int> st;
	std::vector<int> L(n), R(n);
	for (int i = 0; i < n; ++i) {
		while (!st.empty() && a[st.top()] >= a[i]) st.pop();
		L[i] = st.empty() ? 0 : st.top() + 1;
		st.push(i);
	}
	while (!st.empty()) st.pop();
	for (int i = n - 1; i >= 0; --i) {
		while (!st.empty() && a[st.top()] >= a[i]) st.pop();
		R[i] = st.empty() ? n : st.top();
		st.push(i);
	}
	for (int i = 0; i < n; ++i) {
		result = std::max(result, a[i] * (R[i] - L[i]));
	}
	return result;
}

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