SpiralMatrix

 

#include <vector>
#include <iostream>
using namespace std ;
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();

        int sr = 0,er = m-1,sc = 0,ec = n-1 ;
        int count = 0 ;

        while (sr <= er && sc <= ec){
            for (int i = sc; i <=ec ; ++i) {
                ans.push_back(matrix[sr][i]);
                count ++ ;
            }
            sr ++ ;
            if (count == m*n) return ans ;

            for (int i = sr; i <= er; ++i) {
                ans.push_back(matrix[i][ec]);
                count ++ ;
            }
            ec -- ;
            if (count == m*n) return ans ;

            for (int i = ec; i >= sc; --i) {
                ans.push_back(matrix[er][i]);
                count ++ ;
            }
            er -- ;
            if (count == m*n) return ans ;

            for (int i = er; i >= sr; --i) {
                ans.push_back(matrix[i][sc]);
                count ++ ;
            }
            sc ++ ;
            if (count == m*n) return ans ;
        }
        return  ans ;


    }


};