「力扣」第 174 题：地下城游戏（困难）题目链接：https://leetcode-cn.com/problems/d

题目链接：leetcode-cn.com/problems/du…

import java.util.Arrays;

public class Solution {

    public int calculateMinimumHP(int[][] dungeon) {
        int rows = dungeon.length;
        int cols = dungeon[0].length;

        // 理解多加 1 位的原因
        int[][] dp = new int[rows + 1][cols + 1];
        for (int i = 0; i <= rows; i++) {
            Arrays.fill(dp[i], Integer.MAX_VALUE);
        }

        // 初始化，使得 dp[rows - 1][cols - 1] = 1
        dp[rows][cols - 1] = 1;
        dp[rows - 1][cols] = 1;

        for (int i = rows - 1; i >= 0; i--) {
            for (int j = cols - 1; j >= 0; j--) {
                int minVal = Math.min(dp[i + 1][j], dp[i][j + 1]);
                dp[i][j] = Math.max(minVal - dungeon[i][j], 1);
            }
        }
        return dp[0][0];
    }
}