getting time limit exceeds for following test case:

// Example 4     n4 := 13     flights4 := [][]int{{11,12,74},{1,8,91},{4,6,13},{7,6,39},{5,12,8},{0,12,54},{8,4,32},{0,11,4},{4,0,91},{11,7,64},{6,3,88},{8,5,80},{11,10,91},{10,0,60},{8,7,92},{12,6,78},{6,2,8},{4,3,54},{3,11,76},{3,12,23},{11,6,79},{6,12,36},{2,11,100},{2,5,49},{7,0,17},{5,8,95},{3,9,98},{8,10,61},{2,12,38},{5,7,58},{9,4,37},{8,6,79},{9,0,1},{2,3,12},{7,10,7},{12,10,52},{7,2,68},{12,2,100},{6,9,53},{7,4,90},{0,5,43},{11,2,52},{11,8,50},{12,4,38},{7,9,94},{2,7,38},{3,7,88},{9,12,20},{12,0,26},{10,5,38},{12,8,50},{0,2,77},{11,0,13},{9,10,76},{2,6,67},{5,6,34},{9,7,62},{5,3,67}}     src4 := 10     dst4 := 1     k4 := 10     fmt.Println(sol.findCheapestPrice(n4, flights4, src4, dst4, k4)) // Expected Output: -1