Create count-square-submatrices-with-all-ones.cpp

Author: kamyu104

C++/count-square-submatrices-with-all-ones.cpp

@@ -0,0 +1,24 @@
+// Time:  O(m * n)
+// Space: O(1)
+
+class Solution {
+public:
+    int countSquares(vector<vector<int>>& matrix) {
+        for (int i = 1; i < matrix.size(); ++i) {
+            for (int j = 1; j < matrix[0].size(); ++j) {
+                if (!matrix[i][j]) {
+                    continue;
+                }
+                int l = min(matrix[i - 1][j], matrix[i][j - 1]);
+                matrix[i][j] = matrix[i - l][j - l] ? l + 1 : l;
+            }
+        }
+        int result = 0;
+        for (const auto& row : matrix) {
+            for (const auto& x : row) {
+                result += x;
+            }
+        }
+        return result;
+    }
+};