我正在解决旋转NxN矩阵的问题.
似乎我的代码进行了旋转,但在图像上留下了X.
所以我猜它正在不正确地旋转边缘.
我附加了两个图像作为样本输入和输出.
我的代码出了什么问题：
public static void rotateRight(float[][] img){
for (int i=0; i<N/2; i++){
for (int j=i; j<N-i; j++){
int J_COMP = N-j-1; //complement of J
int LEFT = i;
int RIGHT = N-i-1;
int TOP = i;
int BottOM = N-i-1;
float temp = img[J_COMP][LEFT];
img[J_COMP][LEFT] = img[BottOM][J_COMP];
img[BottOM][J_COMP] = img[j][RIGHT];
img[j][RIGHT] = img[TOP][j];
img[TOP][j] = temp;
}
}
}
解决方法
您正在旋转主对角线两次.
修复内循环(参见“修复”评论)
package tests.StackOverflow;
public class Question_20773692 {
private static int N;
public static void main(String[] args) {
float[][] img;
int count;
N=3;
count = 0;
img = new float[N][N];
for(int i=0; i<N; ++i) {
for(int j=0; j<N; ++j) {
img[i][j] = count++;
}
}
printImg(img);
rotateRight(img);
printImg(img);
}
public static void printImg(float[][] img) {
for(int j=0; j<N; ++j) {
System.out.print("-");
}
System.out.println();
for(int i=0; i<N; ++i) {
for(int j=0; j<N; ++j) {
System.out.print((int)(img[i][j]));
}
System.out.println();
}
for(int j=0; j<N; ++j) {
System.out.print("-");
}
System.out.println(); }
public static void rotateRight(float[][] img){
for (int i=0; i<N/2; i++){
for (int j=i; j<N-i; j++){
//for (int j=i+1; j<N-i; j++){ //fix
int J_COMP = N-j-1; //complement of J
int LEFT = i;
int RIGHT = N-i-1;
int TOP = i;
int BottOM = N-i-1;
float temp = img[J_COMP][LEFT];
img[J_COMP][LEFT] = img[BottOM][J_COMP];
img[BottOM][J_COMP] = img[j][RIGHT];
img[j][RIGHT] = img[TOP][j];
img[TOP][j] = temp;
}
}
}
}