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Solution.cpp
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Solution.cpp
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// #Medium #Array #Dynamic_Programming #Matrix #Dynamic_Programming_I_Day_16
// #Big_O_Time_O(m*n)_Space_O(m*n) #2024_05_26_Time_56_ms_(84.56%)_Space_24.5_MB_(55.52%)
#include <vector>
#include <algorithm>
class Solution {
public:
int maximalSquare(std::vector<std::vector<char>>& matrix) {
int m = matrix.size();
if (m == 0) {
return 0;
}
int n = matrix[0].size();
if (n == 0) {
return 0;
}
std::vector<std::vector<int>> dp(m + 1, std::vector<int>(n + 1, 0));
int max = 0;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (matrix[i][j] == '1') {
// 1 + minimum from cell above, cell to the left, cell diagonal upper-left
int next = 1 + std::min(dp[i][j], std::min(dp[i + 1][j], dp[i][j + 1]));
// keep track of the maximum value seen
if (next > max) {
max = next;
}
dp[i + 1][j + 1] = next;
}
}
}
return max * max;
}
};