LeetCode 64. Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right whichminimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

This is very similar with LeetCode 62. Unique Paths

int minPathSum(vector< vector<int> >& grid) {
    int m = grid.size();
    int n = grid[0].size();
    for(int i = 1; i < m; ++i) {
        grid[i][0] += grid[i-1][0];  // initialize
    }

    for(int j = 1; j < n; ++j) {
        grid[0][j] += grid[0][j-1];  // initialize
    }

    for(int i = 1; i < m; ++i) {
        for(int j = 1; j < n; ++j) {
            grid[i][j] += min(grid[i-1][j], grid[i][j-1]);
        }
    }
    return grid[m-1][m-1];
}