0064-minimum-path-sum.js

/**
 * 64. Minimum Path Sum
 * https://leetcode.com/problems/minimum-path-sum/
 * Difficulty: Medium
 *
 * Given a m x n grid filled with non-negative numbers, find a path from
 * top left to bottom right, which minimizes the sum of all numbers along
 * its path.
 *
 * Note: You can only move either down or right at any point in time.
 */

/**
 * @param {number[][]} grid
 * @return {number}
 */
var minPathSum = function(grid) {
  for (let i = 0; i < grid.length; i++) {
    for (let j = 0; j < grid[0].length; j++) {
      if (i === 0 && j === 0) grid[i][j] = grid[i][j];
      else if (i === 0 && j !== 0) grid[i][j] = grid[i][j] + grid[i][j - 1];
      else if (i !== 0 && j === 0) grid[i][j] = grid[i][j] + grid[i - 1][j];
      else grid[i][j] = grid[i][j] + Math.min(grid[i - 1][j], grid[i][j - 1]);
    }
  }

  return grid[grid.length - 1][grid[0].length - 1];
};