there n city connect number flight you give array flight flightsi fromi toi pricei indicate flight city fromi city toi cost priceiyou give integer src dst k return cheap price src dst k stop if route return 1 Example 1input n 4 flight 0110012100201001360023200 src 0 dst 3 k 1Output 700explanationthe graph show aboveThe optimal path 1 stop city 0 3 mark red cost 100 600 700note path city 0123 cheap invalid use 2 stopsExample 2input n 3 flight 011001210002500 src 0 dst 2 k 1Output 200explanationthe graph show aboveThe optimal path 1 stop city 0 2 mark red cost 100 100 200example 3input n 3 flight 011001210002500 src 0 dst 2 k 0output 500explanationthe graph show aboveThe optimal path stop city 0 2 mark red cost 500 Constraints1 n 1000 flightslength n n 1 2flightsilength 30 fromi toi nfromi toi1 pricei 104there multiple flight cities0 src dst k nsrc dst