Flood fill Algorithm

PROBLEM :

Given a 2D screen, location of a pixel in the screen ie(x,y) and a color(K), your task is to replace color of the given pixel and all adjacent same colored pixels with the given color K.

Input:
The first line of input contains an integer T denoting the no of test cases. Then T test cases follow. The first line of each test case contains Two integers N and M denoting the size of the matrix. Then in the next line are N*M space separated values of the matrix. Then in the next line are three values x, y and K.

Output:
For each test case print the space separated values of the new matrix.

Constraints:
1<=T<=10
1<=M[][]<=100

Example:
Input:
2
3 4
0 1 1 0 1 1 1 1 0 1 2 3
0 1 5
2 2
1 1 1 1
0 1 8

Output:
0 5 5 0 5 5 5 5 0 5 2 3
8 8 8 8

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SIMPLE c++ IMPLEMENTATION :
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#include<iostream>
using namespace std;
#define MAX 100

void FloodFill(int screen[MAX][MAX],int ,int ,int ,int ,int ) ;
void UtilFloodFill(int screen[MAX][MAX],int ,int ,int ,int ,int ,int ) ;

int main()
{
int t ;
cin>>t ;

while(t--)
{
   int n,m ;
   cin>>n>>m ;
 
   int screen[MAX][MAX] ;
   for(int i=0;i<n;i++)
       for(int j=0;j<m;j++)
           cin>>screen[i][j] ;
         
   int x,y,k ;
   cin>>x>>y>>k ;
 
   FloodFill(screen,n,m,x,y,k) ;
 
   for(int i=0;i<n;i++)
       for(int j=0;j<m;j++)
           cout<<screen[i][j]<<" " ;
         
   cout<<endl ;
}
return 0;
}

void FloodFill(int screen[MAX][MAX],int n,int m,int x,int y,int k)
{
    int oldC=screen[x][y] ;
    UtilFloodFill(screen,n,m,x,y,oldC,k) ;
}

void UtilFloodFill(int screen[MAX][MAX],int n,int m,int x,int y,int oldC,int newC)
{
    if(x<0||x>=n||y<0||y>=m)
        return ;
       
    if(screen[x][y]!=oldC)
        return ;
       
    screen[x][y]=newC ;
   
    UtilFloodFill(screen,n,m,x-1,y,oldC,newC) ;
    UtilFloodFill(screen,n,m,x+1,y,oldC,newC) ;
    UtilFloodFill(screen,n,m,x,y-1,oldC,newC) ;
    UtilFloodFill(screen,n,m,x,y+1,oldC,newC) ;
}

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