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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-ii-trees-graphs-dynamic-programming/lc-787-cheapest-flights-within-k-stops-implementation

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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-ii-trees-graphs-dynamic-programming/lc-787-cheapest-flights-within-k-stops-implementation

Repovive

LeetCode 787 Cheapest Flights Within K Stops - Implementation - Coding Patterns II: Trees, Graphs & Dynamic Programming | Google Interview Prep | Repovive

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Google Interview Prep6 sections · 128 units7h total

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LeetCode 787 Cheapest Flights Within K Stops - Implementation

The code

Run Bellman-Ford for k + 1 iterations. Copy the distance array each round to respect the stop limit.

function findCheapestPrice(n, flights, src, dst, k):
    dist = array of size n, filled with infinity
    dist[src] = 0
    for i from 0 to k:
        prev = copy of dist
        for [u, v, price] in flights:
            if prev[u] + price < dist[v]:
                dist[v] = prev[u] + price
    if dist[dst] == infinity:
        return -1
    return dist[dst]

$O(k \cdot E)$ time, $O(V)$ space.