标签:opera color struct ems make swap fread link lap
最短路+最小生成树
因为所有东西都只跟加油站有关,那么我们只留加油站就行了。
先预处理出每个点到加油站的最短距离,这个用多源最短路,就是把所有加油站放到堆里,然后就是重构图,我们不用直接连边,计算出每条边的贡献,然后跑最小生成树,这里直接离线查询就行了。
#include<bits/stdc++.h> using namespace std; const int N = 2e5 + 5; namespace IO { const int Maxlen = N * 50; char buf[Maxlen], *C = buf; int Len; inline void read_in() { Len = fread(C, 1, Maxlen, stdin); buf[Len] = ‘\0‘; } inline void fread(int &x) { x = 0; int f = 1; while (*C < ‘0‘ || ‘9‘ < *C) { if(*C == ‘-‘) f = -1; ++C; } while (‘0‘ <= *C && *C <= ‘9‘) x = (x << 1) + (x << 3) + *C - ‘0‘, ++C; x *= f; } inline void fread(long long &x) { x = 0; long long f = 1; while (*C < ‘0‘ || ‘9‘ < *C) { if(*C == ‘-‘) f = -1; ++C; } while (‘0‘ <= *C && *C <= ‘9‘) x = (x << 1) + (x << 3) + *C - ‘0‘, ++C; x *= f; } inline void read(int &x) { x = 0; int f = 1; char c = getchar(); while(c < ‘0‘ || c > ‘9‘) { if(c == ‘-‘) f = -1; c = getchar(); } while(c >= ‘0‘ && c <= ‘9‘) { x = (x << 1) + (x << 3) + c - ‘0‘; c = getchar(); } x *= f; } inline void read(long long &x) { x = 0; long long f = 1; char c = getchar(); while(c < ‘0‘ || c > ‘9‘) { if(c == ‘-‘) f = -1; c = getchar(); } while(c >= ‘0‘ && c <= ‘9‘) { x = (x << 1ll) + (x << 3ll) + c - ‘0‘; c = getchar(); } x *= f; } } using namespace IO; int rd() { int x = 0, f = 1; char c = getchar(); while(c < ‘0‘ || c > ‘9‘) { if(c == ‘-‘) f = -1; c = getchar(); } while(c >= ‘0‘ && c <= ‘9‘) { x = x * 10 + c - ‘0‘; c = getchar(); } return x * f; } int n, m, Q, cnt = 1, s; int head[N], ans[N], c[N], fa[N], d[N], rank[N]; struct edge { int nxt, to, w; } e[N << 1]; struct Edge { int u, v, w; Edge() {} Edge(int u, int v, int w) : u(u), v(v), w(w) {} bool friend operator < (const Edge &a, const Edge &b) { return a.w < b.w; } } E[N]; struct Query { int u, v, id, b; bool friend operator < (const Query &a, const Query &b) { return a.b < b.b; } } que[N]; void link(int u, int v, int w) { e[++cnt].nxt = head[u]; head[u] = cnt; e[cnt].to = v; e[cnt].w = w; } int find(int x) { return x == fa[x] ? x : fa[x] = find(fa[x]); } int main() { read_in(); fread(n); fread(s); fread(m); memset(d, 0x7f7f, sizeof(d)); priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > q; for(int i = 1; i <= s; ++i) { fread(c[i]); d[c[i]] = 0; q.push(make_pair(0, c[i])); } for(int i = 1; i <= m; ++i) { int u, v, w; fread(u); fread(v); fread(w); E[i] = Edge(u, v, w); link(u, v, w); link(v, u, w); } fread(Q); for(int i = 1; i <= Q; ++i) { fread(que[i].u); fread(que[i].v); fread(que[i].b); que[i].id = i; } sort(que + 1, que + Q + 1); while(!q.empty()) { pair<int, int> o = q.top(); q.pop(); int u = o.second; if(o.first > d[u]) continue; for(int i = head[u]; i; i = e[i].nxt) if(d[e[i].to] > d[u] + e[i].w) { d[e[i].to] = d[u] + e[i].w; q.push(make_pair(d[e[i].to], e[i].to)); } } for(int i = 1; i <= m; ++i) E[i].w += d[E[i].u] + d[E[i].v]; sort(E + 1, E + m + 1); for(int i = 1; i <= n; ++i) fa[i] = i; for(int i = 1, j = 0; i <= Q; ++i) { while(j + 1 <= m && E[j + 1].w <= que[i].b) { ++j; int u = find(E[j].u), v = find(E[j].v); if(u == v) continue; if(rank[u] < rank[v]) swap(u, v); rank[u] += rank[v]; fa[u] = v; } ans[que[i].id] = find(que[i].u) == find(que[i].v); } for(int i = 1; i <= Q; ++i) puts(ans[i] ? "TAK" : "NIE"); return 0; }
标签:opera color struct ems make swap fread link lap
原文地址:http://www.cnblogs.com/19992147orz/p/7911808.html