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uva 11057

排序後再找應該會更快

[sourcecode language="cpp"]
//============================================================================
// Name : Exact Sum.cpp
// Date : 2013/3/15 下午12:05:57
// Author : GCA
//============================================================================
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
using namespace std;
#ifdef ONLINE_JUDGE
#define ll "%lld"
#else
#define ll "%I64d"
#endif
typedef unsigned int uint;
typedef long long int Int;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\n")
#define I_de(x,n)for(int i=0;i<n;i++)printf("%d ",x[i]);Pln()
#define De(x)printf(#x"%d\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\
printf("%d ",dp[htx][hty]);}Pln();}
#define M 10010
#define PII pair<int,int>
#define PB push_back
#define oo INT_MAX
#define Set_oo 0x3f
#define Is_debug true
#define debug(...) if(Is_debug)printf("DEBUG: "),printf(__VA_ARGS__)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define eps 1e-6
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
int n;
int x[M];
int to;

int main() {
ios_base::sync_with_stdio(0);
while(~scanf("%d",&n)){
for(int i=0;i<n;i++){
scanf("%d",&x[i]);
}
scanf("%d",&to);
sort(x,x+n);
int minn=oo;
int ans1,ans2;
for(int i=0;i<n;i++){
for(int j=i+1;j<n;j++){
if(x[i]+x[j]==to&&x[j]-x[i]<minn){
minn=x[j]-x[i];
ans1=i;
ans2=j;
}
}
}
printf("Peter should buy books whose prices are %d and %d.\n\n",x[ans1],x[ans2]);

}

}

[/sourcecode]