[Leetcode 26] 62 Unique Paths

Problem:

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).

The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).

How many possible unique paths are there?

class Solution {
public:
int uniquePaths(int m, int n) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int tab[m]
;

for (int i=0; i<m; i++)
for (int j=0; j<n; j++) {
if (i == 0 || j == 0)
tab[i][j] = 1;
else
tab[i][j] = -1;
}

for (int i=1; i<m; i++) {
for (int j=1; j<n; j++) {
if (tab[i][j] == -1)
tab[i][j] = tab[i-1][j] + tab[i][j-1];
}
}

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

View Code

Attention: