数据结构与算法之转圈打印矩阵和旋转正方形矩阵

最新推荐文章于 2022-06-21 14:32:33 发布

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#打印矩阵 #旋转矩阵

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本文介绍两种矩阵操作算法：转圈打印矩阵，即按螺旋顺序遍历矩阵元素；旋转正方形矩阵，实现矩阵的顺时针旋转。通过详细代码解析，帮助读者理解并掌握这两种常见算法。

数据结构与算法之转圈打印矩阵和旋转正方形矩阵


public class Code_PrintMatrixSpiralOrder {

	public static void spiralOrderPrint(int[][] matrix) {
		int tR = 0;
		int tC = 0;
		int dR = matrix.length - 1;
		int dC = matrix[0].length - 1;
		while (tR <= dR && tC <= dC) {
			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--;
			}
		}
	}

	public static void main(String[] args) {
		int[][] matrix = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 },
				{ 13, 14, 15, 16 } };
		spiralOrderPrint(matrix);
	}
}

编译结果

旋转正方形矩阵

题目描述
代码实现

public class Code_RotateMatrix {

    public static void rotate(int[][] matrix) {
        int tR  = 0;
        int tC = 0;
        int dR = matrix.length-1;
        int dC = matrix[0].length-1;
        while (tR<dR){
            rotateEdge(matrix,tR++,tC++,dR--,dC--);
        }
    }

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

    public static void main(String[] args) {
        int[][] matrix = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 },
                { 13, 14, 15, 16 } };
        printMatrix(matrix);
        rotate(matrix);
        System.out.println("=========");
        printMatrix(matrix);
    }
}