64. Minimum Path Sum 

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class Solution {
    public int minPathSum(int[][] grid) {
        int m = grid.length, n = grid[0].length;

        int[][] dp = new int[m][n];
        dp[0][0] = grid[0][0];

        for (int i = 1; i < m; i++) {
            dp[i][0] = dp[i - 1][0] + grid[i][0];
        }
        for (int j = 1; j < n; j++) {
            dp[0][j] = dp[0][j - 1] + grid[0][j];
        }

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

        return dp[m - 1][n - 1];
    }
}

References

64. Minimum Path Sum
剑指 Offer II 099. 最小路径之和