minimum-path-sum.go

package problem0064

func minPathSum(grid [][]int) int {
	// 已经默认 m 和 n 大于 0 了
	m := len(grid)
	n := len(grid[0])

	dp := make([][]int, m)
	for i := range dp {
		dp[i] = make([]int, n)
	}

	dp[0][0] = grid[0][0]

	for i := 1; i < m; i++ {
		dp[i][0] = grid[i][0] + dp[i-1][0]
	}

	for j := 1; j < n; j++ {
		dp[0][j] = grid[0][j] + dp[0][j-1]
	}

	for i := 1; i < m; i++ {
		for j := 1; j < n; j++ {
			dp[i][j] = grid[i][j] + min(dp[i-1][j], dp[i][j-1])
		}
	}

	return dp[m-1][n-1]
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}