Usaco section 1.2 prob miking cows

Greedy, first sort the left point of each time, and then mess up, of course, the line segment tree can also do

/*ID: jusonal1PROG: milk2LANG: C++*/#include <iostream>#include <fstream>#include <string>#include <cstdio>#include <algorithm>#include <map>#include <cstring>using namespace std;struct node{    int left;    int right;    bool operator<(const node& T)const{        return left < T.left;    }};int n;const int maxn = 5000 + 100;node cow[maxn];int main () {    freopen("milk2.in","r",stdin);    freopen("milk2.out","w",stdout);    scanf("%d",&n);    for(int i = 1;i <= n;++i) scanf("%d%d",&cow[i].left,&cow[i].right);    sort(cow + 1,cow + 1 + n);    int cont_time = cow[1].right - cow[1].left,idle_time = 0;    int start = 0,end = 0;    int blank_sum = 0;    start = cow[1].left;    end   = cow[1].right;    for(int i = 1;i <= n;++i){        if(cow[i].left > end ){            idle_time = max(idle_time,cow[i].left - end);            start = cow[i].left;            end   = cow[i].right;        }        else if(cow[i].right > end){            end = cow[i].right;        }        cont_time = max(cont_time,end - start);    }    printf("%d %d\n",cont_time,idle_time);    return 0;}

Usaco section 1.2 prob miking cows