zoukankan      html  css  js  c++  java
  • leetcode 最大子矩阵(5星推荐)

    class Solution {
    public:
        int maximalRectangle(vector<vector<char> > &matrix) {
            if (matrix.empty()) {
                return 0;
            }
            int n = matrix[0].size();
            vector<int> H(n);
            vector<int> L(n);
            vector<int> R(n, n);
            int ret = 0;
            for (int i = 0; i < matrix.size(); ++i) {
                int left = 0, right = n;
                // calculate L(i, j) from left to right
                for (int j = 0; j < n; ++j) {
                    if (matrix[i][j] == '1') {
                        ++H[j];
                        L[j] = max(L[j], left);
                    }
                    else {
                        left = j+1;
                        H[j] = 0; L[j] = 0; R[j] = n;
                    }
                }
                // calculate R(i, j) from right to right
                for (int j = n-1; j >= 0; --j) {
                    if (matrix[i][j] == '1') {
                        R[j] = min(R[j], right);
                        ret = max(ret, H[j]*(R[j]-L[j]));
                    }
                    else {
                        right = j;
                    }
                }
            }
            return ret;
        }
    };
    

    这题自己写的算法复杂度很高,参考了leetcode官方讨论的算法,非常巧妙。

  • 相关阅读:
    Codeforces 977F
    Codeforces 219C
    Codeforces 1132
    Codeforces 660C
    Codeforces 603A
    Codeforces 777C
    Codeforces 677
    JNUOJ 1032
    Codeforces 677D
    Codeforces 835C
  • 原文地址:https://www.cnblogs.com/tgkx1054/p/3111564.html
Copyright © 2011-2022 走看看