leetcode/PrintMatrix.java at master · actor168/leetcode · GitHub

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importjava.util.ArrayList;
publicclassPrintMatrix {

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

System.out.println(newPrintMatrix().printMatrix(matrix));
 }


publicArrayList<Integer> printMatrix(int [][] matrix) {

ArrayList<Integer> res = newArrayList<>();

if (matrix.length <= 0) returnres;

intleft = 0;
intright = matrix[0].length-1;

inttop = 0;
intbottom = matrix.length-1;

if (right == 0 && bottom == 0) {
res.add(matrix[0][0]);
returnres;
 }

if (right == 0) {
for(inti = top; i <= bottom; i++) res.add(matrix[i][right]); // right
returnres;
 }
// System.out.println(left + " " + right + " " + top + " " + bottom);

while(left < right && top < bottom) { // 外圈嵌套
// 循环一圈
for(inti = left; i < right; i++) res.add(matrix[top][i]); // top
for(inti = top; i < bottom; i++) res.add(matrix[i][right]); // right
for(inti = right; i > left; i--) res.add(matrix[bottom][i]); //bottom
for(inti = bottom; i > top; i--) res.add(matrix[i][left]);// left

left++;
right--;
top++;
bottom--;
 }

//System.out.println(left + " " + right + " " + top + " " + bottom);


if (left == right) {
for(inti = top; i <= bottom; i++) res.add(matrix[i][left]); // right
 } elseif (top == bottom) {
for(inti = left; i <= right; i++) res.add(matrix[top][i]); // top
 }

returnres;
 }
}