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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. vector<int> printSpiral(vector<vector<int>> mat) {
  6.  
  7.   // Define ans array to store the result.
  8.   vector<int> ans;
  9.  
  10.   int n = mat.size(); // no. of nows
  11.   int m = mat[0].size(); // no. of columns
  12.  
  13.   // Initialize the pointers reqd for traversal.
  14.   int top = 0, left = 0, bottom = n - 1, right = m - 1;
  15.  
  16.   // Loop until all elements are not traversed.
  17.   while (top <= bottom && left <= right) {
  18.  
  19.     // For moving left to right
  20.     for (int i = left; i <= right; i++)
  21.       ans.push_back(mat[top][i]);
  22.  
  23.     top++;
  24.  
  25.     // For moving top to bottom.
  26.     for (int i = top; i <= bottom; i++)
  27.       ans.push_back(mat[i][right]);
  28.  
  29.     right--;
  30.  
  31.     // For moving right to left.
  32.     if (top <= bottom) {
  33.       for (int i = right; i >= left; i--)
  34.        ans.push_back(mat[bottom][i]);
  35.  
  36.       bottom--;
  37.     }
  38.  
  39.     // For moving bottom to top.
  40.     if (left <= right) {
  41.       for (int i = bottom; i >= top; i--)
  42.         ans.push_back(mat[i][left]);
  43.  
  44.       left++;
  45.     }
  46.   }
  47.   return ans;
  48. }
  49.  
  50. int main() {
  51.  
  52.   //Matrix initialization.
  53.   vector<vector<int>> mat   {{1, 2, 3, 4},
  54.                              {5, 6, 7, 8},
  55. 	                         {9, 10, 11, 12},
  56. 		                     {13, 14, 15, 16}};
  57.  
  58.   vector<int> ans = printSpiral(mat);
  59.  
  60.   for(int i = 0;i<ans.size();i++){
  61.  
  62.       cout<<ans[i]<<" ";
  63.   }
  64.  
  65.   cout<<endl;
  66.  
  67.   return 0;
  68. }
Success #stdin #stdout 0s 5284KB
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https://ideone.com/CXPHpt
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

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