洛谷P1455搭配购买

传送门啦

这是强连通分量与背包的例题

需要注意的就是价值和价格两个数组不要打反了。。

另外 这是双向图！！！

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 1e4 + 4;
const int maxm = 5005;

int n,m,mon;
int c[maxn],w[maxn],u,v;
int C[maxn],W[maxn],f[maxn];
int head[maxn],tot;
int dfn[maxn],low[maxn],ind;
int num[maxn],belong[maxn],cnt,stack[maxn],top;
bool ins[maxn];
struct Edge{
	int to,next,from;
}edge[maxm << 1];

void add(int u,int v){
	edge[++tot].from = u;
	edge[tot].to = v;
	edge[tot].next = head[u];
	head[u] = tot; 
}

int read(){
	char ch = getchar();
	int f = 1 , x = 0;
	while(ch > '9' || ch < '0'){
		if(ch == '-')  f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9'){
		x = x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

void tarjan(int x){
	dfn[x] = low[x] = ++ind;
	stack[++top] = x;
	ins[x] = true;
	for(int i=head[x];i;i=edge[i].next){
		int v = edge[i].to;
		if(!dfn[v]){
			tarjan(v);
			low[x] = min(low[x] , low[v]);
		}
		else if(ins[v])  low[x] = min(low[x] , dfn[v]);
	}
	int k = 0;
	if(dfn[x] == low[x]){
		++cnt;
		do{
			k = stack[top];
			num[cnt]++;
			top--;
			ins[k] = false;
			belong[k] = cnt;
			C[cnt] += c[k];
			W[cnt] += w[k];
		} while(k != x);
	}
}

int main(){
	n = read();  m = read();  mon = read();
	for(int i=1;i<=n;i++){
		c[i] = read();  w[i] = read();
	}
	for(int i=1;i<=m;i++){
		u = read();  v = read();
		add(u,v);
		add(v,u);
	}
	for(int i=1;i<=n;i++)
	  if(!dfn[i])  tarjan(i);
	for(int i=1;i<=cnt;i++)
	  for(int j=mon;j>=C[i];j--)
	    f[j] = max(f[j] , f[j - C[i]] + W[i]);
	printf("%d",f[mon]);
	return 0;
}