我写的时候是这样构图的:先离散化,然后拆点,i和i+1连一条容量为k,费用为0的边。。s和第一个点连容量为INF,费用为0的边, t和终点两一条容量为INF, 费用为0的边。。。然后对于每条边,a的负点和b的正点连一条容量为1,费用为k的边。。。然后跑最大费用最大流。。。跑了1200ms多。。。后来上网百度。。。发现不用拆点。。i和i+1连一条容量为INF,费用为0的边, s和第一个点连容量为k,费用为0的边, t和终点两一条容量为k, 费用为0的边。。就行了。。。跑了500ms多。。。
第一个程序:
#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 1005 #define maxm 100005 #define eps 1e-10 #define mod 1000000007 #define INF 0x3f3f3f3f #define PI (acos(-1.0)) #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 #pragma comment(linker, "/STACK:16777216") typedef long long LL; typedef unsigned long long ULL; //typedef int LL; using namespace std; LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;} LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;} void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();} LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);} // head struct Edge { int v, c, w, next; Edge() {} Edge(int v, int c, int w, int next) : v(v), c(c), w(w), next(next) {} }E[maxm]; struct node { int a, b, w; }p[maxn]; queue<int> q; int H[maxn], cntE; int vis[maxn]; int dis[maxn]; int cap[maxn]; int cur[maxn]; int x[maxn]; int flow, cost, T; int cnt, s, t, n, k, o; void addedges(int u, int v, int c, int w) { E[cntE] = Edge(v, c, w, H[u]); H[u] = cntE++; E[cntE] = Edge(u, 0, -w, H[v]); H[v] = cntE++; } bool spfa(void) { memset(dis, -1, sizeof dis); cur[s] = -1; dis[s] = 0; cap[s] = INF; vis[s] = ++T; q.push(s); while(!q.empty()) { int u = q.front(); q.pop(); vis[u] = T - 1; for(int e = H[u]; ~e; e = E[e].next) { int v = E[e].v, c = E[e].c, w = E[e].w; if(c && dis[v] < dis[u] + w) { dis[v] = dis[u] + w; cap[v] = min(cap[u], c); cur[v] = e; if(vis[v] != T) { vis[v] = T; q.push(v); } } } } if(dis[t] == -1) return false; flow += cap[t]; cost += cap[t] * dis[t]; for(int e = cur[t]; ~e; e = cur[E[e ^ 1].v]) { E[e].c -= cap[t]; E[e ^ 1].c += cap[t]; } return true; } int mcmf(void) { flow = cost = 0; while(spfa()); return cost; } void init(void) { cnt = cntE = T = 0; memset(H, -1, sizeof H); memset(vis, 0, sizeof vis); } int cmp(int a, int b) { return a < b; } void read(void) { scanf("%d%d", &n, &k); for(int i = 0; i < n; i++) { scanf("%d%d%d", &p[i].a, &p[i].b, &p[i].w); x[++cnt] = p[i].a; x[++cnt] = p[i].b; } sort(x+1, x+cnt+1, cmp); int j = 2; for(int i = 2; i <= cnt; i++) if(x[i] != x[i-1]) x[j++] = x[i]; cnt = j - 1; } int find(int xx) { int top = cnt, bot = 1, mid; while(top >= bot) { mid = (top + bot) >> 1; if(x[mid] == xx) break; if(x[mid] > xx) top = mid - 1; else bot = mid + 1; } return mid; } void work(void) { for(int i = 0; i < n; i++) { p[i].a = find(p[i].a); p[i].b = find(p[i].b); } o = cnt, s = 0, t = 2 * o + 1; for(int i = 1; i <= cnt; i++) addedges(i, o + i, k, 0); for(int i = 0; i < n; i++) addedges(o + p[i].a, p[i].b, 1, p[i].w); for(int i = 1; i < cnt; i++) addedges(o + i, i+1, k, 0); addedges(s, 1, INF, 0); addedges(2 * o, t, INF, 0); printf("%d\n", mcmf()); } int main(void) { int _; while(scanf("%d", &_)!=EOF) { while(_--) { init(); read(); work(); } } return 0; }
#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 1005 #define maxm 100005 #define eps 1e-10 #define mod 1000000007 #define INF 0x3f3f3f3f #define PI (acos(-1.0)) #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 #pragma comment(linker, "/STACK:16777216") typedef long long LL; typedef unsigned long long ULL; //typedef int LL; using namespace std; LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;} LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;} void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();} LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);} // head struct Edge { int v, c, w, next; Edge() {} Edge(int v, int c, int w, int next) : v(v), c(c), w(w), next(next) {} }E[maxm]; struct node { int a, b, w; }p[maxn]; queue<int> q; int H[maxn], cntE; int vis[maxn]; int dis[maxn]; int cap[maxn]; int cur[maxn]; int x[maxn]; int flow, cost, T; int cnt, s, t, n, k; void addedges(int u, int v, int c, int w) { E[cntE] = Edge(v, c, w, H[u]); H[u] = cntE++; E[cntE] = Edge(u, 0, -w, H[v]); H[v] = cntE++; } bool spfa(void) { memset(dis, -1, sizeof dis); cur[s] = -1; dis[s] = 0; cap[s] = INF; vis[s] = ++T; q.push(s); while(!q.empty()) { int u = q.front(); q.pop(); vis[u] = T - 1; for(int e = H[u]; ~e; e = E[e].next) { int v = E[e].v, c = E[e].c, w = E[e].w; if(c && dis[v] < dis[u] + w) { dis[v] = dis[u] + w; cap[v] = min(cap[u], c); cur[v] = e; if(vis[v] != T) { vis[v] = T; q.push(v); } } } } if(dis[t] == -1) return false; flow += cap[t]; cost += cap[t] * dis[t]; for(int e = cur[t]; ~e; e = cur[E[e ^ 1].v]) { E[e].c -= cap[t]; E[e ^ 1].c += cap[t]; } return true; } int mcmf(void) { flow = cost = 0; while(spfa()); return cost; } void init(void) { cnt = cntE = T = 0; memset(H, -1, sizeof H); memset(vis, 0, sizeof vis); } int cmp(int a, int b) { return a < b; } void read(void) { scanf("%d%d", &n, &k); for(int i = 0; i < n; i++) { scanf("%d%d%d", &p[i].a, &p[i].b, &p[i].w); x[++cnt] = p[i].a; x[++cnt] = p[i].b; } sort(x+1, x+cnt+1, cmp); int j = 2; for(int i = 2; i <= cnt; i++) if(x[i] != x[i-1]) x[j++] = x[i]; cnt = j - 1; } int find(int xx) { int top = cnt, bot = 1, mid; while(top >= bot) { mid = (top + bot) >> 1; if(x[mid] == xx) break; if(x[mid] > xx) top = mid - 1; else bot = mid + 1; } return mid; } void work(void) { for(int i = 0; i < n; i++) { p[i].a = find(p[i].a); p[i].b = find(p[i].b); } s = 0, t = cnt + 1; for(int i = 0; i < n; i++) addedges(p[i].a, p[i].b, 1, p[i].w); for(int i = 1; i < cnt; i++) addedges(i, i + 1, INF, 0); addedges(s, 1, k, 0); addedges(cnt, t, k, 0); printf("%d\n", mcmf()); } int main(void) { int _; while(scanf("%d", &_)!=EOF) { while(_--) { init(); read(); work(); } } return 0; }