1 #include <bits/stdc++.h> 2 using namespace std; 3 #define _for(i,a,b) for(int i = (a);i < b;i ++) 4 #define _rep(i,a,b) for(int i = (a);i > b;i --) 5 #define INF 0x3f3f3f3f 6 #define pb push_back 7 #define maxn 5000039 8 typedef long long ll; 9 inline ll read() 10 { 11 ll ans = 0; 12 char ch = getchar(), last = ' '; 13 while(!isdigit(ch)) last = ch, ch = getchar(); 14 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar(); 15 if(last == '-') ans = -ans; 16 return ans; 17 } 18 inline void write(ll x) 19 { 20 if(x < 0) x = -x, putchar('-'); 21 if(x >= 10) write(x / 10); 22 putchar(x % 10 + '0'); 23 } 24 int n,m,k; 25 int tot,ver[maxn],Next[maxn],head[maxn],val[maxn]; 26 void add(int x,int y,int t) 27 { 28 ver[++tot] = y,Next[tot] = head[x],head[x] = tot,val[tot] = t; 29 } 30 typedef pair<int,int> P; 31 int d[maxn]; 32 void shortest_path(int s) 33 { 34 priority_queue<P,vector<P>,greater<P>> que; 35 memset(d,0x3f,sizeof(d)); 36 d[s] = 0; 37 que.push(P{0,s}); 38 39 while(!que.empty()) 40 { 41 P p = que.top();que.pop(); 42 int v = p.second; 43 if(d[v] < p.first) continue; 44 for(int i = head[v]; i; i = Next[i]) 45 { 46 // cout << i << endl; 47 int y = ver[i]; 48 int w = val[i]; 49 if(d[y] > d[v] + w) 50 { 51 d[y] = d[v] + w; 52 que.push(P{d[y],y}); 53 } 54 } 55 } 56 } 57 int main() 58 { 59 n = read(), m = read(), k = read(); 60 _for(i,1,m+1) 61 { 62 int u,v,t; 63 u = read();v = read();t = read(); 64 add(u,v,t),add(v,u,t); 65 _for(j,1,k+1) 66 { 67 add(j*n+u,j*n+v,t),add(j*n+v,j*n+u,t); 68 add((j-1)*n+u,j*n+v,0),add((j-1)*n+v,j*n+u,0); 69 } 70 } 71 shortest_path(1); 72 int ans = d[n]; 73 _for(i,1,k+1) 74 ans = min(ans,d[i*n+n]); 75 write(ans); 76 return 0; 77 }