杭电多校 hdu6627 equation

http://acm.hdu.edu.cn/showproblem.php?pid=6627

题意：解绝对值方程并统计解的个数。

解法：签到题，直接模拟小学数学学的零点分段法即可。（数据多直接cin,cout会T，还以为是算法有问题...

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 const int maxn = 1e5+;
 ll s1[maxn],s2[maxn];

 struct node{
     ll a,b;
     double s;
 }g[maxn];

 bool cmp(node p,node q){
     return p.s>q.s;
 }

 struct note{
     ll x,y;
     double s;
 }v[maxn];

 bool cmp1(note p1,note q1){
     return p1.s<q1.s;
 }

 map<double,int> ma;

 int main(){
     ios::sync_with_stdio();
     cin.tie();
     cout.tie();
     int t;
     cin>>t;
     ll n,c;
     while(t--){
         int cnt = ;
         ma.clear();
         cin>>n>>c;
         for(ll i=;i<=n;i++){
             cin>>g[i].a>>g[i].b;
             g[i].s = -1.0*g[i].b/g[i].a;
         }
         sort(g+,g+n+,cmp);
         s1[] = ; s2[] = ;
         for(ll i=;i<=n;i++){
             s1[i] = s1[i-]+g[i].a;
             s2[i] = s2[i-]+g[i].b;
         }
         int flag = ;
         for(ll i=;i<=n;i++){
             ll a1 = s1[n]-*s1[i];
             ll a2 = s2[n]-*s2[i];
             ll s = c-a2;            //a1*x=s
             if(a1==&&s==){
                 flag = ;
                 break;
             }
             else if(a1==){
                 continue;
             }
             else {
                 ll num1 = abs(s);
                 ll num2 = abs(a1);
                 ll gcd = __gcd(num1,num2);
                 double ss = (double)s/a1;
                 if((i==n||ss>g[i+].s)&&(i==||ss<=g[i].s)){
                     if(ma[ss]==){
                         ma[ss]++;
                         v[cnt].x = s/gcd;
                         v[cnt].y = a1/gcd;
                         v[cnt].s = ss;
                         cnt++;
                     }
                 }
             }
         }
         if(flag==){
             cout<<-<<endl;
         }
         else{
             cout<<cnt;
             sort(v,v+cnt,cmp1);
             for(ll i=;i<cnt;i++){
                 if(v[i].x*v[i].y>){
                     cout<<' '<<abs(v[i].x)<<'/'<<abs(v[i].y);
                 }
                 else if(v[i].x*v[i].y==){
                     cout<<' '<<"0/1";
                 }
                 else {
                     cout<<" -"<<abs(v[i].x)<<'/'<<abs(v[i].y);
                 }
             }
             cout<<endl;
         }
     }
     return ;
 }