Shortest path with a fixed number of edges

Question

Find the shortest path through a graph in efficient time, with the additional constraint that the path must contain exactly n nodes.

We have a directed, weighte

Answer 1

let say we want shortest distance from node x to y of k step simple dp solution would be

A[k][x][y] = min over { A[1][i][k] + A[t-1][k][y] } k varies from 0 to n-1

A[1][i][j] = r[i][j]; p[1][i][j]=j;
for(t=2; t<=n; t++)
for(i=0; i