Add solution #787

Author: JoshCrozier

README.md

@@ -597,6 +597,7 @@
 784|[Letter Case Permutation](./0784-letter-case-permutation.js)|Medium|
 785|[Is Graph Bipartite?](./0785-is-graph-bipartite.js)|Medium|
 786|[K-th Smallest Prime Fraction](./0786-k-th-smallest-prime-fraction.js)|Medium|
+787|[Cheapest Flights Within K Stops](./0787-cheapest-flights-within-k-stops.js)|Medium|
 790|[Domino and Tromino Tiling](./0790-domino-and-tromino-tiling.js)|Medium|
 791|[Custom Sort String](./0791-custom-sort-string.js)|Medium|
 796|[Rotate String](./0796-rotate-string.js)|Easy|

solutions/0787-cheapest-flights-within-k-stops.js

@@ -0,0 +1,43 @@
+/**
+ * 787. Cheapest Flights Within K Stops
+ * https://leetcode.com/problems/cheapest-flights-within-k-stops/
+ * Difficulty: Medium
+ *
+ * There are n cities connected by some number of flights. You are given an array flights where
+ * flights[i] = [fromi, toi, pricei] indicates that there is a flight from city fromi to city
+ * toi with cost pricei.
+ *
+ * You are also given three integers src, dst, and k, return the cheapest price from src to dst
+ * with at most k stops. If there is no such route, return -1.
+ */
+
+/**
+ * @param {number} n
+ * @param {number[][]} flights
+ * @param {number} src
+ * @param {number} dst
+ * @param {number} k
+ * @return {number}
+ */
+var findCheapestPrice = function(n, flights, src, dst, k) {
+  const MAX_INT = Number.MAX_SAFE_INTEGER;
+  let prices = new Array(n).fill(MAX_INT);
+  prices[src] = 0;
+
+  for (let i = 0; i <= k; i++) {
+    const tempPrices = [...prices];
+
+    for (const [from, to, price] of flights) {
+      if (prices[from] === MAX_INT) continue;
+
+      const newPrice = prices[from] + price;
+      if (newPrice < tempPrices[to]) {
+        tempPrices[to] = newPrice;
+      }
+    }
+
+    prices = tempPrices;
+  }
+
+  return prices[dst] === MAX_INT ? -1 : prices[dst];
+};