leetcode

Minimum Path Sum

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.

Solution1:

better

  public int minPathSum(int[][] grid) {    int width = grid[0].length;    int height = grid.length;    for (int i = 1; i < width; i++) {      grid[0][i] += grid[0][i - 1];    }    for (int i = 1; i < height; i++) {      grid[i][0] += grid[i - 1][0];      for (int j = 1; j < width; j++) {        grid[i][j] += Math.min(grid[i - 1][j], grid[i][j - 1]);      }    }    return grid[height - 1][width - 1];  }

Solution2:

  public int minPathSum(int[][] grid) {    int width = grid[0].length;    int height = grid.length;    for (int i = 0; i < height; i++) {      for (int j = 0; j < width; j++) {        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 if (i == 0 && j == 0) {          grid[i][j] = grid[i][j];        } else {          grid[i][j] = Math.min(grid[i][j - 1], grid[i - 1][j]) + grid[i][j];        }      }    }    return grid[height - 1][width - 1];  }