Gym 100269D Dwarf Tower（最短路）

思路：给你m个交换条件就是相当于m条路，然后求一发最短路就可以了

#include<bits/stdc++.h>using namespace std;const int maxn = 10000+500;int d[maxn];struct Node{int x,y;Node(){};Node(int xx,int yy):x(xx),y(yy){};};vector<Node>e[maxn];int inq[maxn];int main(){freopen("dwarf.in","r",stdin);freopen("dwarf.out","w",stdout);int n,m;scanf("%d%d",&n,&m);for(int i = 1;i<=n;i++)scanf("%d",&d[i]);for(int i = 1;i<=m;i++){int a,u,v;scanf("%d%d%d",&a,&u,&v);        e[u].push_back(Node(v,a));e[v].push_back(Node(u,a));}queue<int>q;    for(int i =1;i<=n;i++){q.push(i);inq[i]=1;}while(!q.empty()){int now = q.front();q.pop();inq[now]=0;for(int i = 0;i<e[now].size();i++){Node temp = e[now][i];if(d[temp.y]>d[temp.x]+d[now]){d[temp.y]=d[temp.x]+d[now];if(!inq[temp.y])q.push(temp.y);inq[temp.y]=1;}}}printf("%d\n",d[1]);}

Problem D. Dwarf Tower
Input file: dwarf.in
Output file: dwarf.out
Time limit: 2 seconds
Memory limit: 256 megabytes
Little Vasya is playing a new game named “Dwarf Tower”. In this game there are n different items,
which you can put on your dwarf character. Items are numbered from 1 to n. Vasya wants to get the
item with number 1.
There are two ways to obtain an item:
• You can buy an item. The i-th item costs ci money.
• You can craft an item. This game supports only m types of crafting. To craft an item, you give
two particular different items and get another one as a result.
Help Vasya to spend the least amount of money to get the item number 1.
Input
The first line of input contains two integers n and m (1 ≤ n ≤ 10 000; 0 ≤ m ≤ 100 000) — the number
of different items and the number of crafting types.
The second line contains n integers ci — values of the items (0 ≤ ci ≤ 109
).
The following m lines describe crafting types, each line contains three distinct integers ai
, xi
, yi — ai
is
the item that can be crafted from items xi and yi (1 ≤ ai
, xi
, yi ≤ n; ai ̸= xi
; xi ̸= yi
; yi ̸= ai).
Output
The output should contain a single integer — the least amount of money to spend.
Examples
dwarf.in dwarf.out
5 3
5 0 1 2 5
5 2 3
4 2 3
1 4 5
2
3 1
2 2 1
1 2 3
2