顺时针打印矩阵/90度旋转矩阵

Posted 2020-11-15 bowenqianngzhibushiwo

思路：遍历框框

左上角 和右下角的点，可以确定一个矩阵。

左上角（tr,tc）

右下角(dr,dc);

public static void PrintMatrix(int [][] matrix){
int tr=0;
int tc=0;
int dr=matrix.length-1;
int dc=matrix[0].length-1;
while(tc<=dc&&tr<=dr){

printEdge(matrix,tr++,tc++,dr--,dc--); } }

public static void printEdge(int[][] m, int tR, int tC, int dR, int dC) {
   if (tR == dR) {
      for (int i = tC; i <= dC; i++) {
         System.out.print(m[tR][i] + " ");
      }
   } else if (tC == dC) {
      for (int i = tR; i <= dR; i++) {
         System.out.print(m[i][tC] + " ");
      }
   } else {
      int curC = tC;
      int curR = tR;
      while (curC != dC) {
         System.out.print(m[tR][curC] + " ");
         curC++;
      }
      while (curR != dR) {
         System.out.print(m[curR][dC] + " ");
         curR++;
      }
      while (curC != tC) {
         System.out.print(m[dR][curC] + " ");
         curC--;
      }
      while (curR != tR) {
         System.out.print(m[curR][tC] + " ");
         curR--;
      }
   }

 旋转

public static void rotateEdge(int[][] m, int tR, int tC, int dR, int dC) {
        int times = dC - tC; 
        int tmp = 0;
        for (int i = 0; i != times; i++) {
            tmp = m[tR][tC + i];
            m[tR][tC + i] = m[dR - i][tC];
            m[dR - i][tC] = m[dR][dC - i];
            m[dR][dC - i] = m[tR + i][dC];
            m[tR + i][dC] = tmp;
        }
    }

    public static void printMatrix(int[][] matrix) {
        for (int i = 0; i != matrix.length; i++) {
            for (int j = 0; j != matrix[0].length; j++) {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }

 

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