UVA1451

 

二分平均值x，每个数减去x ,    找区间 S[ r ]- S[l]>=0 ,r-l>=m

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#include <iostream> #include <vector> #include <algorithm> using namespace std;  const int N=1e5+5;  #define inf 1e9  int n,m,a[N]; double s[N];     int chk(double md,int ok=0){     int i,k;     s[0]=0;for(i=1;i<=n;i++) s[i]=s[i-1]+a[i]-md;     double t=inf,ans=-inf;     double L=0,R=0 ;           for(i=m;i<=n;i++){         if(s[i-m]<=t){             t=s[i-m]; k=i-m+1;         }         if(s[i]-t>ans+1e-6){             L=k,R=i;             ans=s[i]-t;         }     }     if(ok){         cout<<L<<' '<<R<<endl;     }     return ans>=0;  }  signed main(){     int cas; cin>>cas;     while(cas--){         cin>>n>>m;         int i; char c;         for(i=1;i<=n;i++) cin>>c,a[i]=c-'0';         double l=0,r=1,t;                   while(r-l>1e-6){             double md=(l+r)/2;             if(chk(md)) l=md; else r=md;          }          chk(l+1e-6,1);     }  }