#1992. Find All Groups of Farmland

/**
* @param {number[][]} land
* @return {number[][]}
*/
var findFarmland = function(land) {
let m = land.length;
let n = land[0].length;
let visited = new Array(m);
for(let i = 0; i < m; i++)
visited[i] = new Array(n).fill(false);
let start = [];
let end = [];
function dfs(i,j){
if(i < 0 || i === m || j < 0 || j === n)
return;
if(visited[i][j] === true || land[i][j] === 0)
return;
if(end[0] + end[1] < i + j)
end = [i,j];
visited[i][j] = true;
dfs(i+1,j);
dfs(i,j+1);
}
let ans = [];
for(let i = 0; i < m; i++){
for(let j = 0; j < n; j++){
if(visited[i][j] === false && land[i][j] === 1){
start = [i,j];
end = [i,j];
dfs(i,j);
ans.push([…start,…end]);
}
}
}
return ans;
};