Leetcode174.地下城游戏

题目

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代码（首刷看解析 2024年5月6日）

class Solution {
public:// 动态规划int calculateMinimumHP(vector<vector<int>>& dungeon) {// dp[i][j]从(i,j)出发，到达终点所需要的最少血量int m = dungeon.size();int n = dungeon[0].size();vector<vector<int>> dp(m, vector<int>(n, 0));// dp[i][j] = max(0, min(dp[i + 1][j], dp[i][j + 1] - dungeon[i][j]));dp[m - 1][n - 1] = max(0, -dungeon[m - 1][n - 1]);for (int i = m - 2; i >= 0; i--) {dp[i][n - 1] = max(dp[i + 1][n - 1] - dungeon[i][n - 1], 0);}for (int j = n - 2; j >= 0; j--) {dp[m - 1][j] = max(dp[m - 1][j + 1] - dungeon[m - 1][j], 0);}for (int i = m - 2; i >= 0; i--) {for (int j = n - 2; j >= 0; j--) {dp[i][j] = max(0, min(dp[i + 1][j], dp[i][j + 1]) - dungeon[i][j]);}}return dp[0][0] + 1;}
};

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代码（二刷自解 2024年8月12日）

class Solution {
public:int calculateMinimumHP(vector<vector<int>>& dungeon) {int m = dungeon.size();int n = dungeon[0].size();vector<vector<int>> dp(m, vector<int>(n, 0));dp[m - 1][n - 1] = max(0, -dungeon[m - 1][n - 1]);for (int i = m - 2; i >= 0; i--) {dp[i][n - 1] = max(dp[i + 1][n - 1] - dungeon[i][n - 1], 0);}for (int j = n - 2; j >= 0; j--) {dp[m - 1][j] = max(dp[m - 1][j + 1] - dungeon[m - 1][j], 0);}for (int i = m - 2; i >= 0; i--) {for (int j = n - 2; j >= 0; j--) {dp[i][j] = max(0, min(dp[i + 1][j], dp[i][j + 1]) - dungeon[i][j]);// cout<<"dp["<<i<<"]["<<j<<"]:"<<dp[i][j]<<" ";}// cout<<endl;}return dp[0][0] + 1;}
};