第五届“新思齐”杯程序设计大赛正式赛 F题

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题目链接：here~~

动态规划做的

#include <algorithm>#include <iostream>#include <cstring>#include <cstdlib>#include <string>#include <vector>#include <cstdio>#include <cmath>#include <map>#define FLAG 0using namespace std;int p[10010], b[105];//p数组用来存放到达编号为i的点的最小距离，b用来接收当前层的编号int main(){#if(FLAG)        freopen("in.txt", "r", stdin);//freopen("out.txt", "w", stdout);#endif    int n, m, N, M, i, x, y, z, min, j, w;    while(~scanf("%d%d", &n, &m))    {        memset(p, -1, sizeof(p));        p[0]=0;        for (i = 1; i<=m; i++)        {            scanf("%d%d", &N, &M);            for (j = 1; j<=N; j++)                cin>>b[j];            for (j = 1; j<=M; j++)            {                scanf("%d%d%d", &x, &y, &w);                if (w<=0||p[x]==-1)                    continue;                if (p[y]<0||p[y]>w+p[x])//求到达编号为y的点的最小距离                    p[y]=p[x]+w;            }            min=(1<<30);            for (j = 1; j<=N; j++)            {                if (p[b[j]]==-1)//如果到达倒数第二层的路<=0,跳过                    continue;                if (p[b[j]]<min)                    min=p[b[j]];            }            if (min==(1<<30))//如果到达倒数第二层的路都<=0，输出-1                printf("-1\n");            else                printf("%d\n", min+1);        }        min=(1<<30);        for (j = 1; j<=N; j++)        {            if (p[b[j]]==-1)                continue;            if (p[b[j]]<min)                min=p[b[j]];        }        if (min==(1<<30))            printf("-1\n");        else            printf("%d\n", min+1);    }return 0;}