bloomberg的题，估计真正的IT也不会考这么简单的。
public class Solution {
public int uniquePaths(int m, int n) {
int dp[][] = new int[m][n];
for (int i=0; i<m; i++)
dp[i][0] = 1;
for (int j=0; j<n; j++)
dp[0][j] = 1;
for (int i=1; i<m; i++){
for (int j=1; j<n; j++)
dp[i][j] = dp[i][j-1] + dp[i-1][j];
}
return dp[m-1][n-1];
}
}
