Unique Paths
There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either down or right at any point in time.
Given the two integers m and n, return the number of possible unique paths that the robot can take to reach the bottom-right corner.
The test cases are generated so that the answer will be less than or equal to 2 * 109.
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Example 1:
Input: m = 3, n = 7
Output: 28
Example 2:
Input: m = 3, n = 2
Output: 3
Explanation: From the top-left corner, there are a total of 3 ways to reach the bottom-right corner:
1. Right -> Down -> Down
2. Down -> Down -> Right
3. Down -> Right -> Down
Solution
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class Solution {
public:
int uniquePaths(int m, int n) {
int dicts[m][n];
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
dicts[i][j] = 0;
}
}
for (int i = 0; i < m; i++) {
dicts[i][0] = 1;
}
for (int i = 0; i < n; i++) {
dicts[0][i] = 1;
}
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (dicts[i][j] == 0) {
dicts[i][j] = dicts[i - 1][j] + dicts[i][j - 1];
}
}
}
return dicts[m - 1][n - 1];
}
};
