Merge pull request #46 from JZFamily/master

push to kiritow

LeetCode-CN/48_旋转图像.md

@@ -0,0 +1,159 @@
+## 48. 旋转图像@2018/06/24
+
+### jzf 
+* 4ms
+```c++
+class Solution {
+public:
+    void rotate(vector<vector<int>>& matrix) {
+        
+        int tmp;
+        for(size_t i=0; i<matrix.size();i++)
+        {
+            for(size_t j=i+1;j<matrix.size();j++)
+            {
+                
+                tmp =matrix[i][j];
+                matrix[i][j] =matrix[j][i];
+                matrix[j][i] =tmp;
+            }
+        }
+        for(size_t i =0;i<matrix.size();i++)
+        {
+            reverse(matrix[i].begin(),matrix[i].end());
+        }
+    }
+};
+```
+### kiritow
+* 4ms
+```c++
+class Solution {
+public:
+    void rotate(vector<vector<int>>& matrix) {
+        int n = matrix.size();
+        if (n % 2) // odd number, easy
+        {
+            int mid = n / 2;
+
+            for (int dis = 1; dis <= mid; dis++)
+            {
+                // do chain swap at distance:dis
+                int swap_n = 2 * dis + 1;
+                // save right col
+                vector<int> tvec;
+                int begin_pos = mid - dis;
+                for (int i = 0; i < swap_n; i++)
+                {
+                    tvec.push_back(matrix[begin_pos + i][mid + dis]);
+                }
+                // start rotate
+                // RIGHT <- UPPER
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", begin_pos + i, mid + dis, mid - dis, begin_pos + i);
+                    matrix[begin_pos + i][mid + dis] = matrix[mid - dis][begin_pos + i];
+                }
+                // UPPER <- LEFT
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", mid - dis, begin_pos + i, begin_pos + i, mid - dis);
+                    matrix[mid - dis][begin_pos + (swap_n - i - 1)] = matrix[begin_pos + i][mid - dis];
+                }
+                // LEFT <- DOWNER
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", begin_pos + i, mid - dis, mid + dis, begin_pos + i);
+                    matrix[begin_pos + i][mid - dis] = matrix[mid + dis][begin_pos + i];
+                }
+                // DOWNER <- TEMP
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-tvec[%d]\n", mid + dis, begin_pos + i, i);
+                    matrix[mid + dis][begin_pos + (swap_n - i - 1)] = tvec[i];
+                }
+
+                // debug
+                //print(matrix);
+            }
+        }
+        else // oh, this stuff sucks.
+        {
+            int mid = n / 2 ;
+
+            for (int dis = 1; dis <= mid ; dis++)
+            {
+                // do chain swap at distance:dis
+                int swap_n = 2 * dis;
+                // save right col
+                vector<int> tvec;
+                int begin_pos = mid - dis;
+                for (int i = 0; i < swap_n; i++)
+                {
+                    tvec.push_back(matrix[begin_pos + i][mid + dis - 1]);
+                }
+                // start rotate
+                // RIGHT <- UPPER
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", begin_pos + i, mid + dis, mid - dis, begin_pos + i);
+                    matrix[begin_pos + i][mid + dis - 1] = matrix[mid - dis][begin_pos + i];
+                }
+                // UPPER <- LEFT
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", mid - dis, begin_pos + i, begin_pos + i, mid - dis);
+                    matrix[mid - dis][begin_pos + (swap_n - i - 1)] = matrix[begin_pos + i][mid - dis];
+                }
+                // LEFT <- DOWNER
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-matrix[%d][%d]\n", begin_pos + i, mid - dis, mid + dis, begin_pos + i);
+                    matrix[begin_pos + i][mid - dis] = matrix[mid + dis -1][begin_pos + i];
+                }
+                // DOWNER <- TEMP
+                for (int i = 0; i < swap_n; i++)
+                {
+                    //printf("matrix[%d][%d]<-tvec[%d]\n", mid + dis, begin_pos + i, i);
+                    matrix[mid + dis -1][begin_pos + (swap_n - i - 1)] = tvec[i];
+                }
+
+                // debug
+                //print(matrix);
+            }
+        }
+    }
+};
+```
+### puck
+class Solution
+{
+  public:
+    void rotate(vector<vector<int>> &matrix)
+    {
+        auto n = matrix.size();
+        auto max = n - 1;
+        auto half = n / 2;
+
+        for (int i{}; i < half; ++i)
+        {
+            for (int j{}; j < half; ++j)
+            {
+                std::swap(matrix[i][j], matrix[j][max - i]);
+                std::swap(matrix[i][j], matrix[max - i][max - j]);
+                std::swap(matrix[i][j], matrix[max - j][i]);
+            }
+        }
+
+        if (n == 2 * half + 1)
+        {
+            for (int i{}; i < half; ++i)
+            {
+                std::swap(matrix[i][half], matrix[half][max - i]);
+                std::swap(matrix[i][half], matrix[max - i][half]);
+                std::swap(matrix[i][half], matrix[half][i]);
+            }
+        }
+    }
+};
+```