The question is as follow. (I\'ve modified a little bit)\n\nThere\'s a bidirection graph reqresenting a road network. Each road has a length. And each vertex is a city.\nA person wants to go from a source city to a destination city.\nBut he has limited full energy. For **x** amount of energy left of the person, he can only walk **x** length of the road.\nThere\'re also food stands at certain cities. At the food stand, he can regenerate to the full energy(lets say the full energy is defined as **E**).\nSo given **E**, **source**, **destination**, **cities which has food stands**, and the **graph**, I need to output whether the person can arrive the destination or not. \nHe has full energy initially.\nNotice that a road (or an edge) can be passed unlimited times.\n\nI\'ve come up with an O(n^2) solution. (n is city count)\nAre there any better solution?\nThanks.

The question is as follow. (I\'ve modified a little bit)\n\nThere\'s a bidirection graph reqresenting a road network. Each road has a length. And each vertex is