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class Solution {
public int minPathSum(int[][] grid) {
int[] dp = new int[grid[0].length];
dp[0] = grid[0][0];
for (int i = 1; i < dp.length; i++) {
dp[i] = dp[i - 1] + grid[0][i];
}

for (int i = 1; i < grid.length; i++) {
dp[0] = dp[0] + grid[i][0];
for (int j = 1; j < dp.length; j++) {
dp[j] = Math.min(dp[j], dp[j - 1]) + grid[i][j];
}
}
return dp[dp.length - 1];
}
}

和那个机器人到右下角的题一模一样.

时间复杂度: O(m * n)
空间复杂度: O(n)
m是grid的行数, n是列数.