13.4—动态规划—Maximal Rectangle

描述
Given a 2D binary matrix filled with 0’s and 1’s, find the largest rectangle containing all ones and
return its area.

#include<iostream>#include<vector>#include<stack>using namespace std;int mymax(int a, int b){return a > b ? a : b;}int MaxRectangle(vector<int> input){if (input.size() < 1)return 0;int result = 0;input.push_back(0);stack<int>s;for (int i = 0; i < input.size();){if (s.empty() || input[i] > input[s.top()])s.push(i++);else{int tmp = s.top();s.pop();int index = s.empty() ? i : i - s.top() - 1;result = mymax(result, input[tmp] * index);}}return result;}int MaxRectangle(const vector<vector<int>> &input){if (input.size() < 1)return 0;vector<int> sum(input[0].size(), 0);sum = input[0];int col = input[0].size();int row = input.size();for (int i = 1; i < row; i++){for (int j = 0; j < col; j++){if (input[i][j] == 0)sum[j] = 0;elsesum[j] += input[i][j];}}int maxsum = MaxRectangle(sum);return maxsum;}int main(){vector<int> vec1 = { 0, 1, 0, 1, 1 };vector<int> vec2 = { 0, 1, 0, 1, 1 };vector<int> vec3 = { 0, 1, 1, 1, 1 };vector<int> vec4 = { 0, 0, 1, 1, 1 };vector<vector<int>> input = { vec1, vec2, vec3, vec4 };int maxsum=MaxRectangle(input);cout << "MaxRectangle:" << maxsum << endl;}