对于怪物u,普通攻击打死后产生的怪物为vi。设dis[u]表示打死u的最小花费,那么有
dis[u] = min{s[u] + ∑dis[vi], k[u]}
以这个为松弛条件,跑spfa就可以啦。
然而BZOJ跑了29s...变为倒数rank1
/* Telekinetic Forest Guard */ #include <cstdio> #include <cstring> #include <algorithm> using namespace std; typedef unsigned long long ULL; const int maxn = 200005, maxm = 1000005, maxq = 200005; int n, head[maxn], cnt, q[maxq]; ULL s[maxn], k[maxn], dis[maxn]; bool vis[maxn]; struct _edge { int v, next; } g[maxm << 1]; template <class nt> inline void read(nt &x) { bool f = 0; x = 0; char ch = getchar(); for(; ch < '0' || ch > '9'; ch = getchar()) f = ch == '-' ? 1 : 0; for(; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0'; if(f) x = -x; } inline void add(int u, int v) { g[cnt] = (_edge){v, head[u]}; head[u] = cnt++; } inline void spfa() { int h = 0, t = 0; for(int i = 1; i <= n; i++) dis[i] = k[i], vis[q[t++] = i] = 1; while(h != t) { int u = q[h]; vis[u] = 0; h == maxq - 1 ? h = 0 : h++; ULL res = s[u]; for(int i = head[u]; ~i; i = g[i].next) if(~i & 1) res += dis[g[i].v]; if(res < dis[u]) { dis[u] = res; for(int i = head[u]; ~i; i = g[i].next) if(i & 1) if(!vis[g[i].v]) { q[t] = g[i].v; t == maxq - 1 ? t = 0 : t++; } } } } int main() { read(n); for(int i = 1; i <= n; i++) head[i] = -1; cnt = 0; for(int i = 1, x; i <= n; i++) { read(s[i]); read(k[i]); for(read(x); x; x--) { int u; read(u); add(i, u); add(u, i); } } spfa(); printf("%llu\n", dis[1]); return 0; }
时间: 2024-10-12 02:36:17