劍指 Offer - 19:順時針列印矩陣
阿新 • • 發佈:2018-12-02
題目描述
輸入一個矩陣,按照從外向裡以順時針的順序依次打印出每一個數字,例如,如果輸入如下4 X 4矩陣:
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
則依次打印出數字:1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10題目連結:https://www.nowcoder.com/practice/9b4c81a02cd34f76be2659fa0d54342a
// 模擬
public class Solution {
public ArrayList<Integer> printMatrix (int [][] matrix) {
int left = 0;
int right = matrix[0].length - 1;
int top = 0;
int bottom = matrix.length - 1;
ArrayList<Integer> result = new ArrayList<>();
if (right < 0 || bottom < 0) return result;
while (left <= right && top <= bottom) {
for (int i = left; i <= right; i++) {
result.add(matrix[top][i]);
}
for (int i = top+1; i <= bottom; i++) {
result.add(matrix[i][right]);
}
if (top != bottom) {
for ( int i = right-1; i >= left; i--) {
result.add(matrix[bottom][i]);
}
}
if (left != right) {
for (int i = bottom-1; i >= top+1; i--) {
result.add(matrix[i][left]);
}
}
left++;
right--;
top++;
bottom--;
}
return result;
}
}