Search in a row wise and column wise sorted matrix

Given an n x n matrix, where every row and column is sorted in increasing order. Given a number x, how to decide whether this x is in the matrix. The designed algorithm should have linear time complexity.

Thanks to devendraiiit for suggesting below approach.

1) Start with top right element
2) Loop: compare this element e with x
….i) if they are equal then return its position
…ii) e < x then move it to down (if out of bound of matrix then break return false) ..iii) e > x then move it to left (if out of bound of matrix then break return false)
3) repeat the i), ii) and iii) till you find element or returned false

Implementation:

#include<stdio.h>   /* Searches the element x in mat[][]. If the element is found,     then prints its position and returns true, otherwise prints     "not found" and returns false */ int search(int mat[4][4], int n, int x) {    int i = 0, j = n-1;  //set indexes for top right element    while ( i < n && j >= 0 )    {       if ( mat[i][j] == x )       {          printf("\n Found at %d, %d", i, j);          return 1;       }       if ( mat[i][j] > x )         j--;       else //  if mat[i][j] < x         i++;    }      printf("\n Element not found");    return 0;  // if ( i==n || j== -1 ) }   // driver program to test above function int main() {   int mat[4][4] = { {10, 20, 30, 40},                     {15, 25, 35, 45},                     {27, 29, 37, 48},                     {32, 33, 39, 50},                   };   search(mat, 4, 29);   getchar();   return 0; }

Time Complexity: O(n)

The above approach will also work for m x n matrix (not only for n x n). Complexity would be O(m + n).

Please write comments if you find the above codes/algorithms incorrect, or find other ways to solve the same problem.