The description you provided outlines a programming task for finding a flight itinerary based on specified criteria. Here's a breakdown of the task:

Description:

This task involves finding flight itineraries between two cities $($source and destination$).$

A list of flights is given. Each flight has a from, to$,$ and price field.

You need to determine all possible routes from src to dest with up to k stops and return these routes along with the total price for each.

Input Format:

First line: Three integers, src$,$ dest, and k$,$ which specify the source city index, destination city index, and the maximum number of stops allowed, respectively.

Following lines: Lists of flights where each list consists of flights in the format $[$from$\_$i$,$ to$\_$i$,$ price$\_$i$].$

Output Format:

Output all possible routes from src to dest with at most k stops, listing the flights and the total price.

Constraints:

$1<=$ n $<=100$ where n is the number of cities.

The total number of flights is $($n $*($n$-1)/2).$

Flight data format: $[$from$,$ to$,$ price$]$ with price within a valid range.

Each city index is valid and within the bounds.

To solve this, we can use a graph traversal technique such as a modified depth$-$first search $($DFS$)$ or breadth$-$first search $($BFS$)$ which considers the maximum k stops constraint. Each node in the graph represents a city, and each edge represents a flight.

Here's a basic C implementation that you can use as a starting point. This version sets up the problem and uses a simple DFS to explore routes from src to dest with constraints on the number of stops.

sample input

$4031($ n src dst k$)$

$[[0,1,100],[1,2,100],[2,0,100],[1,3,600],[2,3,200]]($src$1,$dst$1,$price$)$

#include

#include

#include

#define MAX$\_$CITIES $100$

#define MAX$\_$FLIGHTS $4950//$ n $=100$

typedef struct $\{$

int from;

int to;

int price;

$\}$ Flight;

Flight flights$[$MAX$\_$FLIGHTS$]$;

int flight$\_$count $=0$;

int visited$[$MAX$\_$CITIES$]$;

int min$\_$cost $=$ INT$\_$MAX;

Flight path$[$MAX$\_$CITIES$]$;

int path$\_$length $=0$;

int n$,$ src$,$ dest, k;

void add$\_$flight$($int from, int to$,$ int price$)\{$

flights$[$flight$\_$count$].$from $=$ from;

flights$[$flight$\_$count$].$to $=$ to;

flights$[$flight$\_$count$].$price $=$ price;

flight$\_$count$++$;

$\}$

void print$\_$route$($Flight path$[],$ int length, int total$\_$price$)\{$

printf$("",$ total$\_$price$)$;

for $($int i $=0$; i $<$ length; i$++)\{$

printf$("(\%$d $->\%$d $[\%$d$])",$ path$[$i$].$from, path$[$i$].$to$,$ path$[$i$].$price$)$;

$\}$

printf$("$

$")$;

$\}$

void dfs$($int current$\_$city, int depth, int total$\_$price$)\{$

if $($depth $>$ k$)$ return; $//$ k $$

if $($current$\_$city $==$ dest$)\{$

print$\_$route$($path$,$ path$\_$length, total$\_$price$)$;

if $($total$\_$price $<$ min$\_$cost$)\{$

min$\_$cost $=$ total$\_$price;

$\}$

return;

$\}$

for $($int i $=0$; i $<$ flight$\_$count; i$++)\{$

if $($flights$[$i$].$from $==$ current$\_$city && $!$visited$[$flights$[$i$].$to$])\{$

visited$[$flights$[$i$].$to$]=1$;

path$[$path$\_$length$++]=$ flights$[$i$]$;

dfs$($flights$[$i$].$to$,$ depth $+1,$ total$\_$price $+$ flights$[$i$].$price$)$;

path$\_$length$--$;

visited$[$flights$[$i$].$to$]=0$;

$\}$

$\}$

$\}$

int main$()\{$

scanf$("\%$d $\%$d $\%$d $\%$d$",$ &n$,$ &src$,$ &dest, &k$)$;

int from, to$,$ price;

while $($scanf$("\%$d $\%$d $\%$d$",$ &from, &to$,$ &price$)!=$ EOF$)\{$

add$\_$flight$($from$,$ to$,$ price$)$;

$\}$

visited$[$src$]=1$;

dfs$($src$,0,0)$;

if $($min$\_$cost $==$ INT$\_$MAX$)\{$

printf$("-1)$;

$\}$ else $\{$

printf$("\%$d

$",$ min$\_$cost$)$;

$\}$

return $0$;

$\}$