uva10487

来源：互联网发布：日本转运公司知乎编辑：程序博客网时间：2024/05/21 10:38

#include<iostream>#include<algorithm>using namespace std;int n,m,k,cases,sum,arr[1005],S[1000000];void calsum(){k=0;for (int i=0;i<n-1;i++){for (int j=i+1;j<n;j++){S[k++]=arr[i]+arr[j];}}sort(S,S+k);}int abs(int t){return t>0?t:-t;}void bisearch(){int low=0;int high=k-1;int mid;int flag=0;while(low<=high){mid=(low+high)/2;if (S[mid]<sum){low=mid+1;}else if (S[mid]>sum){high = mid-1;}else{flag = 1;break;}}if (flag)cout<<"Closest sum to "<<sum<<" is "<<sum<<"."<<endl;else{if (mid==0){cout<<"Closest sum to "<<sum<<" is "<<S[mid]<<"."<<endl;}else if (abs(S[mid-1]-sum)<abs(S[mid]-sum)){cout<<"Closest sum to "<<sum<<" is "<<S[mid-1]<<"."<<endl;}else cout<<"Closest sum to "<<sum<<" is "<<S[mid]<<"."<<endl;}}int main(){cases=0;while (cin>>n&&n){cases++;for (int i=0;i<n;i++){cin>>arr[i];}calsum();cin>>m;cout<<"Case "<<cases<<":"<<endl;while(m--){cin>>sum;bisearch();}}return 0;}

很简单的一题，排序后二分查找找最接近的值，为什么会wa呢？一直搞不懂

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