ZOJ 1221Risk_Floyd - Dijkstra

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这题非常适合我这样的新手做，，，刚学了Floyd 和 Dijkstra，正好用这题练习一下

http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=39591

这题既可以用Floyd ，也可以用Dijkstra。。

Dijkstra：

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <vector>#include <set>#include <queue>#include <map>#include <stack>#define PI 3.1415926#define E 1000using namespace std;typedef long long LL;const int INT_MAX = 99999999;int grap[110][110];int dis[110],vis[110];void Dij(int u0){    for(int i = 1; i <= 20; i++)    {        dis[i] = INT_MAX;        vis[i] = 0;    }    dis[u0] = 0;    for(int i = 1; i <= 20; i++)    {        int MIN = INT_MAX;        int u = u0;        for(int j = 1; j <= 20; j++)        {            if(!vis[j] && dis[j] < MIN)            {                u = j;                MIN = dis[j];            }        }        vis[u] = 1;        for(int j = 1; j <= 20; j++)        {            if(!vis[j] && (MIN + grap[u][j] < dis[j]))                dis[j] = MIN + grap[u][j];        }    }}int main(){//    freopen("in.txt","r",stdin);    int Case = 1;    int n;    while(~scanf("%d",&n))    {        for(int i = 1; i <= 20; i++)        {            for(int j = 1; j <= 20; j++)                grap[i][j] = grap[j][i] = INT_MAX;        }        int a;        while( n -- )        {            scanf("%d",&a);            grap[1][a] = 1;        }        for(int i = 2; i < 20; i++)        {            scanf("%d",&a);            int t;            for(int j = 0; j < a; j++)            {                scanf("%d",&t);                grap[i][t] = 1;                grap[t][i] = 1;            }        }        int b;        printf("Test Set #%d\n",Case ++);        scanf("%d",&b);        while(b --)        {            int f,e;            scanf("%d%d",&f,&e);            Dij(f);            printf("%d to %d: %d\n",f,e,dis[e]);        }        printf("\n");    }    return 0;}

Floyd ：

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <vector>#include <set>#include <queue>#include <map>#include <stack>#define PI 3.1415926#define E 1000using namespace std;typedef long long LL;const int INT_MAX = 99999999;int grap[110][110];//int dis[110],vis[110];void Floyd(){    for(int k = 1; k <= 20; k++)        for(int i = 1; i <= 20; i++)            for(int j = 1; j <=20; j++)                if(grap[i][k] + grap[k][j] < grap[i][j])                {                    grap[i][j] = grap[i][k] + grap[k][j];                }}int main(){//    freopen("in.txt","r",stdin);    int Case = 1;    int n;    while(~scanf("%d",&n))    {        for(int i = 1; i <= 20; i++)        {            for(int j = 1; j <= 20; j++)            {                grap[i][j] = grap[j][i] = INT_MAX;            }        }        int a;        while( n -- )        {            scanf("%d",&a);            grap[1][a] = 1;        }        for(int i = 2; i < 20; i++)        {            scanf("%d",&a);            int t;            for(int j = 0; j < a; j++)            {                scanf("%d",&t);                grap[i][t] = 1;                grap[t][i] = 1;            }        }        Floyd();        int b;        printf("Test Set #%d\n",Case ++);        scanf("%d",&b);        while(b --)        {            int f,e;            scanf("%d%d",&f,&e);            printf("%d to %d: %d\n",f,e,grap[f][e]);        }        printf("\n");    }    return 0;}

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