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  • [leetcode] Maximal Square

    Problem:

    Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 1's and return its area.

    For example, given the following matrix:

    1 0 1 0 0
    1 0 1 1 1
    1 1 1 1 1
    1 0 0 1 0
    

    Return 4.


    比较详细的解法在这里:

    https://leetcode.com/discuss/38489/easy-solution-with-detailed-explanations-8ms-time-and-space

    附上最终的代码:

     1 int maximalSquare(vector<vector<char>>& matrix) 
     2 {
     3     if (matrix.empty()) return 0;
     4     int m = matrix.size(), n = matrix[0].size();
     5     vector<int> dp(m + 1, 0);
     6     int maxsize = 0, pre = 0;
     7     for (int j = 0; j < n; j++) {
     8         for (int i = 1; i <= m; i++) {
     9             int temp = dp[i];
    10             if (matrix[i - 1][j] == '1') {
    11                 dp[i] = min(dp[i], min(dp[i - 1], pre)) + 1;
    12                 maxsize = max(maxsize, dp[i]);
    13             }
    14             else dp[i] = 0;
    15             pre = temp;
    16         }
    17     }
    18     return maxsize * maxsize;
    19 }
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  • 原文地址:https://www.cnblogs.com/wangke1020/p/4559312.html
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