区间相交问题（贪心）－算法设计与分析

//区间相交问题int n;struct node{int x,y;bool operator<(const node &s)const{if(y!=s.y) return y<s.y;return x<s.x;}}a[100];int main(){cin>>n;int ans=0;for(int i=0;i<n;i++){cin>>a[i].x>>a[i].y;if(a[i].x>a[i].y) swap(a[i].x,a[i].y);}int left=a[0].x,right=a[0].y;for(int i=1;i<n;i++){if((a[i].x>=left && a[i].x<=right) || (a[i].y>=left && a[i].y<=right) || (a[i].x<=left && a[i].y>=right))ans++;else left=a[i].x,right=a[i].y;}cout<<ans<<endl;return 0;}/*Input:310 2010 1520 15Output:2*/