《编程之美》 2.19 区间重合判断

// 2.19.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

struct area
{
int begin;
int end;
};

bool compare(area& a,area& b)
{
return a.begin<b.begin;
}
int _tmain(int argc, _TCHAR* argv[])
{
int arr[] = {2, 5, 3, 4, 3, 9, 11, 15};
vector<area> vec;
area a;
for(int i=0;i<sizeof(arr)/sizeof(arr[0]);)
{
a.begin=arr[i++];
a.end=arr[i++];
vec.push_back(a);
}
sort(vec.begin(),vec.end(),compare);//排序
//
cout << "after sort: " << endl;

for (int i = 0; i < vec.size(); i ++)

cout << "(" << vec[i].begin << ", " << vec[i].end << ") ";

cout << endl;
//

//合并

for(int i=1;i<vec.size();)
{
if(vec[i].begin<=vec[i-1].end && vec[i].end>=vec[i-1].end)
{
vec[i-1].end=vec[i].end;
vec.erase(vec.begin()+i);
}
else if(vec[i].begin<=vec[i-1].end && vec[i].end<vec[i-1].end)
{
vec.erase(vec.begin()+i);
}
else
++i;
}
//

cout << "after merger :" << endl;

for (int i = 0; i < vec.size(); i ++)

cout << "(" << vec[i].begin << ", " << vec[i].end << ") ";

cout << endl;

//二分查找

area target;//设置源区间
target.begin=2;
target.end=8;

int first=0;
int last=vec.size()-1;

bool flag=false;

while(first<=last)
{
int mid=(first+last)/2;
if(vec[mid].begin<=target.begin&&vec[mid].end>=target.end)
{
flag=true;
break;
}
else if(vec[mid].end<target.begin)
first=mid+1;
else if(vec[mid].begin>target.end)
last=mid-1;
else
break;

}
if(flag) cout<<"true"<<endl;
else cout<<"false"<<endl;

return 0;
}