Add leetcode 221

LeetCode/221.cpp

@@ -0,0 +1,85 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <algorithm>
+#include <iostream>
+#include <vector>
+#include <queue>
+using namespace std;
+
+// Leetcode 221
+
+class Solution
+{
+public:
+    int maximalSquare(vector<vector<char>>& matrix)
+    {
+        vector<vector<int>> vec;
+        for (int i = 0; i < matrix.size(); i++)
+        {
+            vector<int> tvec(matrix[i].size(), 0);
+            vec.push_back(tvec);
+        }
+
+        for (int i = 0; i < matrix.size(); i++)
+        {
+            if (matrix[i][0] == '1')
+            {
+                vec[i][0] = 1;
+            }
+            else
+            {
+                vec[i][0] = 0;
+            }
+        }
+
+        for (int j = 0; j < matrix[0].size(); j++)
+        {
+            if (matrix[0][j] == '1')
+            {
+                vec[0][j] = 1;
+            }
+            else
+            {
+                vec[0][j] = 0;
+            }
+        }
+
+        for (int i = 1; i < matrix.size(); i++)
+        {
+            for (int j = 1; j < matrix[i].size(); j++)
+            {
+                if (matrix[i][j] == '0')
+                {
+                    vec[i][j] = 0;
+                    continue;
+                }
+
+                if (matrix[i][j] == '1')
+                {
+                    if (vec[i - 1][j] && vec[i][j - 1] && vec[i-1][j-1])
+                    {
+                        vec[i][j] = min(min(vec[i - 1][j], vec[i][j - 1]), vec[i - 1][j - 1]) + 1;
+                    }
+                    else
+                    {
+                        vec[i][j] = 1;
+                    }
+                }
+            }
+        }
+
+        int nMax = 0;
+        for (int i = 0; i < matrix.size(); i++)
+        {
+            for (int j = 0; j < matrix[i].size(); j++)
+            {
+                cout << vec[i][j] << " ";
+                nMax = max(nMax, vec[i][j]);
+            }
+            cout << endl;
+        }
+
+        return nMax * nMax;
+    }
+};