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/// 剑指 Offer 47. 礼物的最大价值
/// <https://leetcode.cn/problems/li-wu-de-zui-da-jie-zhi-lcof/>

pub struct Solution;

#[allow(unused)]
impl Solution {
	pub fn max_value(grid: Vec<Vec<i32>>) -> i32 {
		if grid.is_empty() {
			return 0
		}
		let mut dp = vec![vec![0; grid[0].len()]; grid.len()];
		for i in 0..grid.len() {
			for j in 0..grid[0].len() {
				if i == 0 && j == 0 {
					dp[i][j] = grid[i][j];
				} else if i == 0 {
					dp[i][j] = dp[i][j - 1] + grid[i][j];
				} else if j == 0 {
					dp[i][j] = dp[i - 1][j] + grid[i][j];
				} else {
					dp[i][j] = std::cmp::max(dp[i - 1][j], dp[i][j - 1]) + grid[i][j];
				}
			}
		}
		dp[grid.len() - 1][grid[0].len() - 1]
	}
}

#[cfg(test)]
mod tests {
	use super::*;

	#[test]
	fn test() {
		let grid = vec![vec![1, 3, 1], vec![1, 5, 1], vec![4, 2, 1]];
		assert_eq!(Solution::max_value(grid), 12);
	}
}