Create 48.cpp

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Kirigaya Kazuto 2018-06-24 12:42:41 +08:00 committed by GitHub
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LeetCode-CN/48.cpp Normal file
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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);
}
}
}
};