733, Flood Fill

====

733, Flood Fill

====

DFS,

from each un-visited node/island problems

====

1. 題目給予一個vec<vec<int>>M

一個起始的座標

以及變更的新數值

2. 定義一個vec<vec<bool>>visited

DFS( M, visited, i, j, m, n, new )走過上下左右的同值/同於起始 的所有node

====

class Solution{

void DFS( vec<vec<int>>& matrix, vec<vec<bool>>&visited, int i, int j, int m, int n, int old, int new){

  if( i<0 || j<0 || i>=m || j>=n || matrix(i,j)!=old || visited(i,j) ) return;

  visited(i,j)= true;

  matrix(i,j)= new;

  DFS( matrix, visited, i-1, j, m, n, matrix(i,j), new)

  DFS i+1

  DFS j-1

  DFS j+1

}

vec<vec<int>> FloodFill( vec<vec<int>>& matrix, int x, int y, int newColor ){

  int m= matirx.size(), n= matrix[0].size()

  vec<vec<bool>> visited= (m, false)

  if matrix(x,y)!=newColor

    DFS( matrix, visited, x, y, matrix(x,y), newColor)

  return matrix

}