不同的路径

class Solution {
public:
/**
* @param n, m: positive integer (1 <= n ,m <= 100)
* @return an integer
*/
int uniquePaths(int m, int n) {
// wirte your code here
int a[m]
;
for(int i = 0; i < m; ++i)
a[i][0] = 1;
for(int j = 0; j < n; ++j)
a[0][j] = 1;
for(int i =1;i < m;++i){
for(int j =1;j<n;++j){
a[i][j]=a[i-1][j]+a[i][j-1];
}
}
return a[m-1][n-1];
}
};