OJ-Problems-Source/HDOJ/4807_autoAC.cpp

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#include<stdio.h>
#include<string.h>
#include<queue>
#include<math.h>
#define N_node 2500 + 50
#define N_edge 10000 + 100
#define INF 2000000000
using namespace std;
typedef struct
{
int from ,to ,next ,cost ,flow;
}STAR;
STAR E[N_edge];
int list[N_node] ,tot;
int mer[N_edge] ,s_x[N_node];
void add(int a ,int b ,int c ,int d)
{
E[++tot].from = a;
E[tot].to = b;
E[tot].cost = c;
E[tot].flow = d;
E[tot].next = list[a];
list[a] = tot;
}
bool spfa(int s ,int t ,int n)
{
int mark[N_node] = {0};
for(int i = 0 ;i <= n ;i ++)
s_x[i] = INF;
queue<int>q;
q.push(s);
mark[s] = 1 ,s_x[s] = 0;
memset(mer ,255 ,sizeof(mer));
while(!q.empty())
{
int xin ,tou;
tou = q.front();
q.pop();
mark[tou] = 0;
for(int k = list[tou] ;k ;k = E[k].next)
{
xin = E[k].to;
if(s_x[xin] > s_x[tou] + E[k].cost && E[k].flow)
{
s_x[xin] = s_x[tou] + E[k].cost;
mer[xin] = k;
if(!mark[xin])
{
mark[xin] = 1;
q.push(xin);
}
}
}
}
return mer[t] != -1;
}
int M_C_Flow(int s ,int t ,int n ,int k)
{
if(!k) return 0;
int minflow ,sum_peo = k ,now_peo = 0 ,list_time = 0 ,ans = INF;
while(spfa(s ,t ,n))
{
minflow = INF;
for(int i = mer[t] ;i + 1 ;i = mer[E[i].from])
if(minflow > E[i].flow) minflow = E[i].flow;
for(int i = mer[t] ;i + 1 ;i = mer[E[i].from])
E[i].flow -= minflow ,E[i^1].flow += minflow;
sum_peo -= (s_x[t] - list_time) * now_peo + minflow;
list_time = s_x[t] ,now_peo += minflow;
int now = s_x[t] + (int)ceil((1.0 * (sum_peo < 0 ? 0 : sum_ ))/now_peo);
if(ans > now) ans = now;
if(sum_peo < 1) break;
}
return ans;
}
int main ()
{
int n ,m ,k ,i ,a ,b ,c;
while(~scanf("%d %d %d" ,&n ,&m ,&k))
{
memset(list ,0 ,sizeof(list));
tot = 1;
for(i = 1 ;i <= m ;i ++)
{
scanf("%d %d %d" ,&a ,&b ,&c);
a ++ ,b ++;
add(a ,b ,1 ,c) ,add(b ,a ,-1 ,0);
}
int ans = M_C_Flow(1 ,n ,n ,k);
ans == INF ? puts("No solution"):printf("%d\n" ,ans);
}
return 0;
}