Unique Paths
描述
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?
Above is a 3 x 7 grid. How many possible unique paths are there?
Note: m and n will be at most 100.
题解
package algorithms
//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?
func uniquePaths(m int, n int) int {
if m == 0 || n == 0 {
return 0
}
matrix := make([][]int, n)
for y := range matrix {
matrix[y] = make([]int, m)
matrix[y][0] = 1
}
for x := range matrix[0] {
matrix[0][x] = 1
}
for y := 1; y < n; y++ {
for x := 1; x < m; x++ {
matrix[y][x] = matrix[y][x-1] + matrix[y-1][x]
}
}
return matrix[n-1][m-1]
}