From 4c793f2b8f5ba797dbd983dea829cd774e9806b4 Mon Sep 17 00:00:00 2001
From: Kirito <1362050620@qq.com>
Date: Sun, 24 Jun 2018 12:42:41 +0800
Subject: [PATCH] Create 48.cpp

---
 LeetCode-CN/48.cpp | 96 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 LeetCode-CN/48.cpp

diff --git a/LeetCode-CN/48.cpp b/LeetCode-CN/48.cpp
new file mode 100644
index 0000000..0f78784
--- /dev/null
+++ b/LeetCode-CN/48.cpp
@@ -0,0 +1,96 @@
+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);
+            }
+        }
+    }
+};