Algorithm-rotate image (matrix processing)

Today in Lintcode did a problem, I think about the practice, made, but felt it necessary to record.

Test instructions

Given a nxn two-dimensional matrix to represent the image, 90 degrees clockwise rotation of the image.

Examples:

Given a rectangle [[1,2],[3,4]],90] Clockwise, return [[3,1],[4,2]]

Challenge:

Can you do it in situ?

1. Solving ideas

At first glance, this problem is really very simple. Here I use a graph to express the problem-solving ideas:

2. Code

1      Public voidRotateint[] matrix) {2         if(Matrix.length = = 0 | | matrix[0].length = = 0) {3             return;4         }5         //rotate clockwise 270 degrees6          for(inti = 0; i < matrix.length; i++) {7              for(intj = 0; J < I; J + +) {8                 inttemp =Matrix[i][j];9MATRIX[I][J] =Matrix[j][i];TenMatrix[j][i] =temp; One             } A         } -         //rotate counterclockwise 180 degrees -          for(inti = 0; i < matrix.length; i++) { the              for(intj = 0; J < Matrix[0].length/2; J + +) { -                 inttemp =Matrix[i][j]; -MATRIX[I][J] = matrix[i][matrix[0].length-1-j]; -Matrix[i][matrix[0].length-1-J] =temp; +             } -         } +}

Algorithm-rotate image (matrix processing)