剑指offer66题--Java实现，c++实现和python实现 19.顺时针打印矩阵

题目描述

输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，例如，如果输入如下4 X 4矩阵： 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.

C++

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {       
        if (matrix.empty()) return {};
        int m = matrix.size(), n = matrix[0].size();
        vector<int> spiral(m * n);
        int u = 0, d = m - 1, l = 0, r = n - 1, k = 0;
        while (true) {   
            for (int col = l; col <= r; col++) spiral[k++] = matrix[u][col];
            if (++u > d) break;
            // right
            for (int row = u; row <= d; row++) spiral[k++] = matrix[row][r];
            if (--r < l) break;
            // down
            for (int col = r; col >= l; col--) spiral[k++] = matrix[d][col];
            if (--d < u) break;
            // left
            for (int row = d; row >= u; row--) spiral[k++] = matrix[row][l];
            if (++l > r) break;
             // up
        }
        return spiral;
    }
};

JAVA

import java.util.ArrayList;
public class Solution {
    public ArrayList<Integer> printMatrix(int [][] array) {
            ArrayList<Integer> result = new ArrayList<Integer> ();
            if(array.length==0) return result;
            int n = array.length,m = array[0].length;
            if(m==0) return result;
            int layers = (Math.min(n,m)-1)/2+1;//这个是层数
            for(int i=0;i<layers;i++){
                for(int k = i;k<m-i;k++) result.add(array[i][k]);//左至右
                for(int j=i+1;j<n-i;j++) result.add(array[j][m-i-1]);//右上至右下
                for(int k=m-i-2;(k>=i)&&(n-i-1!=i);k--) result.add(array[n-i-1][k]);//右至左
                for(int j=n-i-2;(j>i)&&(m-i-1!=i);j--) result.add(array[j][i]);//左下至左上
            }
            return result;       
        }
}

Python

# -*- coding:utf-8 -*-
class Solution:
    # matrix类型为二维列表，需要返回列表
    def printMatrix(self, matrix):
            # write code here
            result = []
            while(matrix):
                result += matrix.pop(0)
                if not matrix or not matrix[0]:
                    break
                matrix[:] = list(map(list, zip(*matrix)))[::-1]
            return result