# Spiral Matrix Problem

## Description

LeetCode Problem 54.

Given an m x n matrix, return all elements of the matrix in spiral order.

Example 1:

``````1
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Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,2,3,6,9,8,7,4,5]
``````

Example 2:

``````1
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Input: matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]
``````

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 10
• -100 <= matrix[i][j] <= 100

## Sample C++ Code

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class Solution {
public:
vector<int> spiralOrder(vector<vector<int>>& matrix) {
vector<int> ans;
int m = matrix.size();
if (m == 0) return ans;
int n = matrix[0].size();

vector<vector<int>> dir = { {0,1}, {1,0}, {0,-1}, {-1, 0} };
int diff = 0, turns = 0, i = 0;
int x = 0, y = 0;

while (i < m*n) {
ans.push_back(matrix[x][y]);
if ((turns%4 == 0 && y+diff >= n-1) ||
(turns%4 == 1 && x+diff >= m-1) ||
(turns%4 == 2 && y-diff <= 0) ||
(turns%4 == 3 && x-diff <= 0)){
turns ++;
if (turns%4 == 3)
diff ++;
}
x += dir[turns%4][0];
y += dir[turns%4][1];
i ++;
}
return ans;
}
};
``````