【HDU】2544 最短路

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复习最短路

SPFA：

#include <cstdio>#include <cstring>#define C (c=nc())using namespace std;struct wjnsb {int s,t,val;}e[10005];int m,n;int dis[105];inline char nc(void){static char ch[100010],*p1=ch,*p2=ch;return p1==p2&&(p2=(p1=ch)+fread(ch,1,100010,stdin),p1==p2)?EOF:*p1++;}inline void read(int &n){static char c;int f=1;n=0;C;while (c<'0'||c>'9') c=='-'?f=-1,C:C;while (c>='0'&&c<='9') n=(n<<3)+(n<<1)+c-48,C;return (void)(n*=f);}int main(void){while (1){read(n),read(m);if (n==0&&m==0) return 0;memset(dis,0x3f,sizeof(dis));dis[1]=0;register int i,j;for (i=1;i<=2*m;i+=2) read(e[i].s),read(e[i].t),read(e[i].val),e[i+1].val=e[i].val,e[i+1].s=e[i].t,e[i+1].t=e[i].s;for (i=1;i<=n;++i){for (j=1;j<=2*m;++j){if (dis[e[j].s]+e[j].val<dis[e[j].t]) dis[e[j].t]=dis[e[j].s]+e[j].val;}}printf("%d\n",dis[n]);}}