64. Minimum Path Sum (Graph; DP)
Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.
Note: You can only move either down or right at any point in time.
class Solution { public: int minPathSum(vector<vector<int>> &grid) { if(grid.empty()) return 0; vector<vector<int>> dp(grid.size(), vector<int>(grid[0].size(), 0)); dp[0][0] = grid[0][0]; for(int i = 1; i< grid[0].size(); i++) { dp[0][i] = dp[0][i-1] + grid[0][i]; } for(int i = 1; i< grid.size(); i++) { dp[i][0] = dp[i-1][0] + grid[i][0]; } for(int i = 1;i<grid.size(); i++) { for(int j = 1; j< grid[0].size(); j++) { dp[i][j] = min(dp[i-1][j], dp[i][j-1]) + grid[i][j]; } } return dp[grid.size()-1][grid[0].size()-1]; } };