Spiral Matrix

Desicription

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

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2
3
4
5
[
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

Solution

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class Solution {
private:
int n, m;
bool isValid(vector<vector<int> >& matrix, int x, int y){
if(x < 0 || x >= n || y < 0 || y >= m || matrix[x][y] == INT_MIN)
return 0;
return 1;
}
public:
vector<int> spiralOrder(vector<vector<int> >& matrix) {
vector<int> res;
if(matrix.empty())
return res;
n = matrix.size();
m = matrix[0].size();
int x = 0;
int y = 0;
while(1){
bool flag = 0;
while(isValid(matrix, x, y))
res.push_back(matrix[x][y]), matrix[x][y] = INT_MIN, y++, flag = 1;
y--;
x++;
while(isValid(matrix, x, y))
res.push_back(matrix[x][y]), matrix[x][y] = INT_MIN, x++, flag = 1;
x--;
y--;
while(isValid(matrix, x, y))
res.push_back(matrix[x][y]), matrix[x][y] = INT_MIN, y--, flag = 1;
y++;
x--;
while(isValid(matrix, x, y))
res.push_back(matrix[x][y]), matrix[x][y] = INT_MIN, x--, flag = 1;
x++;
y++;
if(!flag)
return res;
}
}
};