Counter-clockwise print matrix, counter-clockwise Matrix

Counter-clockwise print matrix, counter-clockwise Matrix

The life of graduate students is boring. Recently I want to go out and look for internships. I will review the data structure. I did not review the data structure in my freshman year. I was despised during the interview. When I saw a senior student, it should be the test question of Kingsoft:

To a matrix, print the matrix counter-clockwise, for example:

1	12	11	10
2	13	16	9
3	14	15	8
4	5	6	7

Print it out in a counter-clockwise manner: 1 2 3 4 5... 14 15 16

At first glance, this question is very simple, that is, it can be done in two cycles. In fact, it is not as simple as you think, because every cycle changes. I have referred to some ideas on solving problems on the Internet. Now let's talk about my ideas.

1. Define a direction d = (d + 1) % 4, then d =, 2 and 3 indicate four directions

2. print the current row col: k-> j of the matrix, column row: m-> n, initial condition: col = 0, row = 0, k = 0, j = 3, m = 0, n = 3

3. When the first column is printed, k + = 1, col = n

4. When the last row is printed, n-= 1, row = j

5. Print the last column, j-= 1, col = m

6. Print the first line, m + = 1, row = k

...

7. termination conditions: m = n & k = j

The following shows the code I wrote in java:

Int [] [] p = {,}, {,}; int col = 0, row = 0; // The current column and row int m = 0, n = 3, k = 0, j = 3; // col: m-> n row: k-> j int d =-1; // indicates the direction while (true) {d = (d + 1) % 4; switch (d) {case 0: for (int I = m; I <= n; I ++) {System. out. print (p [I] [row] + "");} col = n; k + = 1; // prevent repeated break; case 1: for (int I = k; I <= j; I ++) {System. out. print (p [col] [I] + "");} row = j; n-= 1; // prevent repeated break; case 2: for (int I = n; i> = m; I --) {System. out. print (p [I] [row] + "");} col = m; j-= 1; break; case 3: for (int I = j; i> = k; I --) {System. out. print (p [col] [I] + "");} row = k; m + = 1; break; default: break ;} if (m = n & k = j) {break ;}}