CutOffTreesForGolfEvent.js

/**
 * 675. Cut Off Trees for Golf Event
 * @param {number[][]} forest
 * @return {number}
 */
var cutOffTree = function (forest) {
  let forestLine = [];
  for (i = 0; i < forest.length; i++)
    for (j = 0; j < forest[0].length; j++)
      if (forest[i][j] !== 0) forestLine.push([forest[i][j],
        [i, j]
      ]);
  forestLine.sort((a, b) => {
    return a[0] - b[0];
  });
  if (forestLine.length == 1 && !(forestLine[0][0] == 0 && forestLine[0][1] == 0)) return -1;
  forestLine.unshift([0, [0, 0]]);
  let bfs = (beg, end) => {
    let q = [
      [beg[0], beg[1]]
    ];
    let step = 0;
    let visited = Array(forest.length).fill().map(() => Array(forest[0].length).fill(0));
    visited[beg[0]][beg[1]] = 1;
    while (q.length != 0) {
      let len = q.length;
      for (i = 0; i < len; i++) {
        let dirs = [
          [q[0][0] - 1, q[0][1]],
          [q[0][0] + 1, q[0][1]],
          [q[0][0], q[0][1] - 1],
          [q[0][0], q[0][1] + 1]
        ];
        for ([qx, qy] of dirs) {
          if (qx > -1 && qy > -1 && qx < forest.length && qy < forest[0].length && forest[qx][qy] != 0 && visited[qx][qy] != 1) {
            q.push([qx, qy]);
            visited[qx][qy] = 1;
          }
        }
        let curr = q.shift();
        if (curr[0] == end[0] && curr[1] == end[1]) return step;
      }
      step++;
    }
    return -1;
  };

  let res = 0;
  for (let i = 0; i < forestLine.length - 1; i++) {
    let beg = forestLine[i][1];
    let end = forestLine[i + 1][1];
    let q = [
      [beg[0], beg[1]]
    ];
    let ret = bfs(beg, end);
    if (ret == -1) return -1;
    else res += ret;
  }
  return res;
};