Bzoj1520: [poi2006] szk-Schools

1520: [poi2006] szk-schoolstime limit: 5 sec memory limit: 64 MB
Submit: 342 solved: 173
[Submit] [Status] Descriptioninputoutput: If a feasible solution exists, the minimum output cost is required. Otherwise, output nie. Sample input5.
1 1 2 3
1 1 5 1
3 2 5 5
4 1 5 10
3 3 3 1
Sample output9
Hintsource

Question:

Bare minimum fee Max stream...

Code:

  1 #include<cstdio>  2   3 #include<cstdlib>  4   5 #include<cmath>  6   7 #include<cstring>  8   9 #include<algorithm> 10  11 #include<iostream> 12  13 #include<vector> 14  15 #include<map> 16  17 #include<set> 18  19 #include<queue> 20  21 #include<string> 22  23 #define inf 1000000000 24  25 #define maxn 500+100 26  27 #define maxm 250000 28  29 #define eps 1e-10 30  31 #define ll long long 32  33 #define pa pair<int,int> 34  35 #define for0(i,n) for(int i=0;i<=(n);i++) 36  37 #define for1(i,n) for(int i=1;i<=(n);i++) 38  39 #define for2(i,x,y) for(int i=(x);i<=(y);i++) 40  41 #define for3(i,x,y) for(int i=(x);i>=(y);i--) 42  43 #define mod 1000000007 44  45 using namespace std; 46  47 inline int read() 48  49 { 50  51     int x=0,f=1;char ch=getchar(); 52  53     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();} 54  55     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();} 56  57     return x*f; 58  59 } 60 int n,m,k,mincost,maxflow,tot=1,s,t,head[maxn],q[maxm],d[maxn],from[2*maxm]; 61  62 bool v[maxn]; 63  64 struct edge{int from,next,go,v,c;}e[2*maxm]; 65  66 void ins(int x,int y,int z,int w) 67  68 { 69  70     e[++tot].go=y;e[tot].from=x;e[tot].v=z;e[tot].c=w;e[tot].next=head[x];head[x]=tot; 71  72 } 73  74 void insert(int x,int y,int z,int w) 75  76 { 77  78     ins(x,y,z,w);ins(y,x,0,-w); 79  80 } 81  82 bool spfa() 83  84 { 85  86     for (int i=s;i<=t;i++){v[i]=0;d[i]=inf;} 87  88     int l=0,r=1,y;q[1]=s;d[s]=0;v[0]=1; 89  90     while(l!=r) 91  92     { 93  94         int x=q[++l];if(l==maxn)l=0;v[x]=0; 95  96         for (int i=head[x];i;i=e[i].next) 97  98          if(e[i].v&&d[x]+e[i].c<d[y=e[i].go]) 99 100          {101 102             d[y]=d[x]+e[i].c;from[y]=i;103 104             if(!v[y]){v[y]=1;q[++r]=y;if(r==maxn)r=0;}105 106          }107 108     }109 110     return d[t]!=inf;111 112 }113 114 void mcf()115 116 {117 118     while(spfa())119 120     {121 122         int tmp=inf;123 124         for(int i=from[t];i;i=from[e[i].from]) tmp=min(tmp,e[i].v);125 126         mincost+=d[t]*tmp;maxflow+=tmp;127 128         for(int i=from[t];i;i=from[e[i].from]){e[i].v-=tmp;e[i^1].v+=tmp;}129 130     }131 132 }133 134 int main()135 136 {137 138     freopen("input2.txt","r",stdin);139 140     freopen("output3.txt","w",stdout);141 142     n=read();s=0;t=2*n+1;143     for1(i,n)144     {145         insert(s,i,1,0);insert(i+n,t,1,0);146         int x=read(),l=read(),r=read(),y=read();147         for2(j,l,r)insert(i,j+n,1,y*(abs(j-x)));148     }149     mcf();150     if(maxflow==n)printf("%d\n",mincost);else puts("NIE");151 152     return 0;153 154 }

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Bzoj1520: [poi2006] szk-Schools