面试题20 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.

class Solution {
public:
void printCircle(vector<vector<int> > matrix, int start, vector<int> &v){
int rows = matrix.size(), columns = matrix[0].size();
int endx = columns - 1 - start;
int endy = rows - 1 - start;
for (int i = start; i <= endx; i++)
v.push_back(matrix[start][i]);
if (start < endy){
for (int i = start + 1; i <= endy; i++)
v.push_back(matrix[i][endx]);
}
if (start < endx && start < endy){
for (int i = endx - 1; i >= start; i--)
v.push_back(matrix[endy][i]);
}
if (start < endx && start < endy - 1){
for (int i = endy - 1; i >= start + 1; i--){
v.push_back(matrix[i][start]);
}
}
}

vector<int> printMatrix(vector<vector<int> > matrix) {
vector<int> v;
int rows = matrix.size(), columns = matrix[0].size();
int start = 0;
while (columns > start * 2 && rows > start * 2){
printCircle(matrix, start, v);
start++;
}
return v;
}
};