30 Day Challenge Day 14 | Leetcode 1219. Path with Maximum Gold

题解

Medium | Backtracking

class Solution {
public:
    int getMaximumGold(vector<vector<int>>& grid) {
        int ret = 0;
        for(int i = 0; i < grid.size(); i++) {
            for(int j = 0; j < grid[0].size(); j++) {
                helper(grid, i, j, 0, ret);
            }
        }
        return ret;
    }
    
    void helper(vector<vector<int>>& grid, int x, int y, int curr,int& max_gold) {
        if(x < 0 || x >= grid.size() || y < 0 || y >= grid[0].size() || grid[x][y] == 0) {
            return;
        }
        
        int dirs[4][2] = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

        if(curr+grid[x][y] > max_gold) {
            max_gold = curr + grid[x][y];
        }
        
        int temp = grid[x][y];
        curr = curr + grid[x][y];
        grid[x][y] = 0;

        for(auto& dir : dirs) {
            int next_x = x + dir[0];
            int next_y = y + dir[1];
            helper(grid, next_x, next_y, curr, max_gold);
        }
        
        grid[x][y] = temp;
    }
};