hdu 1142 A Walk Through the Forest

无聊的一题

#include<iostream>#include<queue>#include<cstring>#include<vector>#define maxn 1010#define inf 1<<30using namespace std;int n,m;vector<int>mapp[maxn];int vaule[maxn][maxn];int d[maxn];int dp[maxn];void init(){for(int i=0;i<=n;i++) mapp[i].clear(),d[i]=inf,dp[i]=0;dp[2]=1;for(int i=0;i<=n;i++){for(int j=0;j<=n;j++) vaule[i][j]=inf;}}void input(){for(int i=0;i<m;i++){int x,y,z;cin>>x>>y>>z;if(vaule[x][y]==inf){mapp[x].push_back(y);mapp[y].push_back(x);}if(z<vaule[x][y]){vaule[x][y]=z;vaule[y][x]=z;}}}void bfs(){queue<int>q;int x,y;x=2;d[2]=0;q.push(x);while(q.size()){int x=q.front();q.pop();for(int i=0;i<mapp[x].size();i++){y=mapp[x][i];if(d[y]>d[x]+vaule[x][y]){d[y]=d[x]+vaule[x][y];q.push(y);}}}//for(int i=1;i<=n;i++) cout<<d[i]<<" ";//cout<<endl;}int dfs(int x){if(dp[x]) return dp[x];for(int i=0;i<mapp[x].size();i++){int y=mapp[x][i];if(d[y]<d[x]){dp[x]+=dfs(y);}}return dp[x];}int main(){cin.sync_with_stdio(false);while(cin>>n>>m&&n){init();input();bfs();cout<<dfs(1)<<endl;}return 0;}