【最短路】HDOJ 2363 Cycling

二分+枚举+最短路。。。不错的题。。。

#include <iostream>#include <queue> #include <stack> #include <map> #include <set> #include <bitset> #include <cstdio> #include <algorithm> #include <cstring> #include <climits>#include <cstdlib>#include <cmath>#include <time.h>#define maxn 105#define maxm 10005#define eps 1e-10#define mod 1000000007#define INF 1e9+10#define lowbit(x) (x&(-x))#define mp make_pair#define ls o<<1#define rs o<<1 | 1#define lson o<<1, L, mid #define rson o<<1 | 1, mid+1, R typedef long long LL;typedef unsigned long long ULL;//typedef int LL;using namespace std;struct Edge{int v, c;Edge *next;}pool[maxm], *edges, *H[maxn];struct node{int id, d;bool operator < (const node& b) const {return d > b.d;}}now, tmp;priority_queue<node> q;int dist[maxn], vis[maxn];int h[maxn], hh[maxn];int n, m;void addedges(int u, int v, int c){edges->v = v;edges->c = c;edges->next = H[u];H[u] = edges++;}void init(void){edges = pool;memset(H, 0, sizeof H);}int cmp(int a, int b){return a < b;}void read(void){int a, b, c;scanf("%d%d", &n, &m);for(int i = 1; i <= n; i++) scanf("%d", &h[i]), hh[i] = h[i];for(int i = 1; i <= m; i++) {scanf("%d%d%d", &a, &b, &c);addedges(a, b, c);addedges(b, a, c);}sort(h+1, h+n+1, cmp);}int dijstra(int s, int low, int high){for(int i = 1; i <= n; i++) dist[i] = INF, vis[i] = 0;tmp.id = s, tmp.d = 0;if(hh[s] >= low && hh[s] <= high) q.push(tmp);dist[s] = 0;while(!q.empty()) {now = q.top(), q.pop();int x = now.id, d = now.d;if(vis[x]) continue;vis[x] = 1;for(Edge *e = H[x]; e; e = e->next) {if(dist[e->v] > dist[x] + e->c && hh[e->v] >= low && hh[e->v] <= high) {dist[e->v] = dist[x] + e->c;tmp.id = e->v, tmp.d = dist[e->v];q.push(tmp);}}}return dist[n];}void work(void){int top, bot, low, mid, res, ans = h[n], t;for(int i = 1; i <= n; i++) {low = h[i], top = h[n], bot = h[i], res = -1;//printf("AAA %d\n", i);//printf("%d %d\n", dijstra(1, 3, 5), dist[n]);while(top >= bot) {mid = (top + bot) >> 1;if(dijstra(1, low, mid) != INF) res = mid, top = mid-1;else bot = mid+1;}if(res != -1 && res - low <= ans) {if(res - low < ans) ans = res - low, t = dijstra(1, low, res);else t = min(t, dijstra(1, low, res));}}printf("%d %d\n", ans, t);}int main(void){int _;while(scanf("%d", &_)!=EOF) {while(_--) {init();read();work();}}return 0;}