Z形打印

package 每日算法学习打卡.算法打卡.七月份.七月二十七号;public class test1 {public static void main(String[] args) {int[][] matrix = {{1, 2, 3, 4},{5, 6, 7, 8},{9, 10, 11, 12},};print(matrix);}static void print(int[][] matrix) {int r = 0, m = matrix.length;int l = 0, n = matrix[0].length;boolean l2r = true;while (r < m && l < n) {if (l2r) {System.out.println(matrix[r][l] + " ");//如果在走上坡路if (r == 0 && l < n - 1) {l2r = !l2r;l++;continue;//如果已经走到末尾了，行号就进行减一操作} else if (r > 0 && l == n - 1) {l2r = !l2r;r++;continue;//其余的情况都是在走上坡路} else {r--;l++;}} else {//如果是在走下坡路System.out.println(matrix[r][l] + " ");//如果走到左边界的时候，就向下走一格if(l == 0 && r <m-1){l2r = !l2r;r++;continue;}else if( r == m-1){l2r = !l2r;l++;continue;}else{r++;l--;}}}}
}

边界为1的最大子方阵

package 每日算法学习打卡.算法打卡.七月份.七月二十七号;public class test2 {public static int solve(int[][] matrix, int N) {int n = N; // 阶数boolean flag = false;while (n > 0) {for (int i = 0; i < N; i++, flag = false) {if (i + n > N)break;for (int j = 0; j < N; j++, flag = false) {if (j + n > N)break;// 当前节点开始查看是否满足均为1int r = i, c = j;while (c < j + n) { // 往右走if (matrix[r][c] == 0) {flag = true;break;}c++;}if (flag) {continue;}c--; // 复原while (r < i + n) { // 往下走if (matrix[r][c] == 0) {flag = true;break;}r++;}if (flag) {continue;}r--;while (c >= j) { // 往左走if (matrix[r][c] == 0) {flag = true;break;}c--;}if (flag) {continue;}c++;while (r >= i) { // 往上走if (matrix[r][c] == 0) {flag = true;break;}r--;}if (flag) {continue;}r++;return n;}}n--;}return n; // 全是0，直接返回}public static void main(String[] args) {int[][] matrix = {{0, 1, 1, 1, 1},{0, 1, 0, 0, 1},{0, 1, 0, 0, 1},{0, 1, 1, 1, 1},{0, 1, 0, 1, 1}};int res = solve(matrix, 5);System.out.println("result: " + res);}}