题目地址:
https://www.lintcode.com/problem/unique-paths/description
给定一个矩阵,从左上到右下格子一共有多少种不同走法。每次只能向右或者向下走一格,不能出界。代码如下:
import java.util.Arrays;
public class Solution {
/**
* @param m: positive integer (1 <= m <= 100)
* @param n: positive integer (1 <= n <= 100)
* @return: An integer
*/
public int uniquePaths(int m, int n) {
// write your code here
int[][] dp = new int[m][n];
Arrays.fill(dp[0], 1);
for (int i = 0; i < m; i++) {
dp[i][0] = 1;
}
for (int i = 1; i < m; i++) {
for (int j = 1; j < n; j++) {
dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
}
}
return dp[m - 1][n - 1];
}
}
时空复杂度 。