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