hdu a strang lift

来源：互联网发布：云计算四种部署模式编辑：程序博客网时间：2024/06/05 17:40
按得最短路做的，DP 搜索也能搞
#include <cstdio>#include <cstring>#include <algorithm>#include <vector>#include <queue>using namespace std;#define MAX_N 10000#define INF 0xfffftypedef pair<int, int> P;int n,v,u;int G[MAX_N][MAX_N];int d[MAX_N];bool used[MAX_N];int a[MAX_N];void dijkstra(int v){        for(int i = 1;i <= n; i++){                d[i] = G[v][i];        }        fill(used, used + n, false);        d[v] = 0;        used[v] = 1;        for(int i = 2; i <= n; i++){                int flag = v,min = INF;                for(int u = 1;u < n; u++){                         if(!used[u] && d[u] < min){                               flag = u;                               min = d[u];                        }                }                used[flag] = 1;                for(int j = 1; j <=n;j++){                        if(!used[j] && G[flag][j] < INF){                                int newd = d[flag] + G[flag][j];                                if(newd < d[j])                                        d[j] = newd;                        }                }        }}int main(){        while(scanf("%d", &n) && n){                scanf("%d%d",&v, &u);                for(int i = 1;i <= n; i++)                        for(int j = 1;j <= n; j++)                                G[i][j] = INF;                for(int i = 1;i <= n; i++){                        scanf("%d", &a[i]);                        G[i][i + a[i]] = 1;                        if(i >= a[i] + 1){                                G[i][i - a[i]] = 1;                        }                }                                dijkstra(v);                if(d[u] >= INF)                        printf("-1\n");                else                         printf("%d\n", d[u]);        }        return 0;}
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