2012 National Team Tree mutual test

You give a free communication to FIG weighted, each edge is black or white. Let you find a minimum weight of exactly need spanning tree white side stripe. Topic guarantee solvability

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This question is not very good feel called by generations also need cnt practice

Anyway, how are bzoj data on the water

#include<bits/stdc++.h>
#define re return
#define ll long long
#define inc(i,l,r) for(int i=l;i<=r;++i)

using namespace std;
template<typename T>inline void rd(T&x)
{
    char c;bool f=0;
    while((c=getchar())<'0'||c>'9')if(c=='-')f=1;
    x=c^48;
    while((c=getchar())>='0'&&c<='9')x=x*10+(c^48);
    if(f)x=-x;
}

const int maxn=50005,maxm=100005;
int n,m,sum,need,ans,hd[maxn],fa[maxn];

struct node{
    int fr,to,val,flag;
    bool operator<(node a)const 
    {
        if(val==a.val)re flag<a.flag;
        re val<a.val;
    }
}e[maxm];

inline int find ( int x) 
{ 
    D x == ago [x]? x ago [x] = find (for [x]); 
} 

Inline int vivi ( int x) 
{ 
    inc (and 1 , m) f (E [i] .flag) e [i] .val + = x; 
    
    inc (i, 1 , n) does [i] = i; 
    
    Luckily (e + 1 , m + e + 1 );
    int cnt = 0 , all = 0 ; 
    
    sum = 0 ; 
    
    Inc. (and 1 , m) 
    { 
        int f1 = find (e [i] .fr) f2 =find(e[i].to);
        if(f1!=f2)
        {
            ++tot;
            sum+=e[i].val;
            if(!e[i].flag)
                ++cnt;
            fa[f1]=f2;
            if(tot==n-1)break;
        }
    }
    
    inc(i,1,m)
    if(!e[i].flag)
        e[i].val-=x;
    if(cnt<need)re 0;
    ans=sum-cnt*x;
// but if need be the case, the original is not in the right side and it ranged 
    Re . 1 ; 
} 

int main () 
{ 
    The freopen ( " in.txt " , " R & lt " , stdin); 
    RD (n-), RD (m ); RD (need); 
    inc is (I, . 1 , m) 
    { 
        RD (E [I] .fr); RD (E [I] .to);
         ++ E [I] .fr; ++ E [I ] .to; 
        RD (E [I] .val); RD (E [I] .flag); 
    } 
    
    int L = - 100 , R & lt = 100 ;
     the while (L <= R & lt) 
    { 
        int MID = (L + R & lt ) >> 1 ;
         IF(vivi(mid))
             l=mid+1;
        else r=mid-1;
    }
    
    printf("%d",ans);
    re 0;
}