Cf Edu 15 C Cellular Network 二分

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http://codeforces.com/problemset/problem/702/C二分搜索与每个城市最近的信号塔取能满足所有城市的最小值#include<stdio.h>#include<string>#include<cstring>#include<queue>#include<algorithm>#include<functional>#include<vector>#include<iomanip>#include<math.h>#include<iostream>#include<sstream>#include<set>#include<map>using namespace std;const int MAX=100005;int A[MAX]={0},B[MAX]={0};int main(){    cin.sync_with_stdio(false);    int n,m;    cin>>n>>m;    for (int i=0;i<n;i++)        cin>>A[i];    for (int i=0;i<m;i++)        cin>>B[i];    int Ans=0;    for (int i=0;i<n;i++)    {        int d=lower_bound(B,B+m,A[i])-B;        int res;        if (d==0)            res=B[d]-A[i];        else if (d==m)            res=A[i]-B[d-1];        else            res=min(B[d]-A[i],A[i]-B[d-1]);        Ans=max(Ans,res);    }    cout<<Ans<<endl;    return 0;}直接二分答案#include <bits/stdc++.h>  using namespace std;  __int64 a[1111111];  __int64 b[1111111];  int main()  {      int n,m;      while (~scanf("%d%d",&n,&m))      {          for (int i = 0 ; i < n ; i++ )          {              scanf("%I64d",&a[i]);          }          for (int i = 0 ; i < m ; i++ )          {              scanf("%I64d",&b[i]);          }          __int64 l = 0,r = 2000000008;          while(l < r)          {              __int64 mid = (l + r) / 2;              int flag = 0;              int x = 0;              for (int i = 0 ; i < n ; i++ )              {                  if ( x >= m)                  {                      flag = 1;                      break;                  }                  if (fabs(b[x] -a[i]) <= mid)                  {                      continue;                  }                  else                   {                      x++;                      i--;                  }              }              if ( flag == 1)              {                  l = mid + 1;              }              else               {                  r = mid;              }              //printf("%I64d\n",r);          }          printf("%I64d\n",l);      }  }
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