洛谷P2970 [USACO09DEC]自私的放牧Selfish Grazing
一道贪心题
1 #include <cstdio> 2 #include <cmath> 3 #include <cstdlib> 4 #include <cstring> 5 #include <iostream> 6 #include <iomanip> 7 #include <string> 8 #include <algorithm> 9 #define For(i,j,k) for(int i=j;i<=k;i++) 10 #define Dow(i,j,k) for(int i=j;i>=k;i--) 11 using namespace std ; 12 13 const int N = 50011 ; 14 struct node{ 15 int s,t ; 16 }seg[N]; 17 int n,ans ; 18 int dp[N] ; 19 20 inline int read() 21 { 22 int x = 0 , f = 1 ; 23 char ch = getchar() ; 24 while(ch<'0'||ch>'9') { if(ch=='-') f = -1 ; ch = getchar(); } 25 while(ch>='0'&&ch<='9') { x = x * 10+ch-48 ; ch = getchar(); } 26 return x * f ; 27 } 28 inline bool cmp(node a,node b) 29 { 30 if(a.t!=b.t) return a.t < b.t ; 31 return a.s < b.s ; 32 } 33 int main() 34 { 35 n = read() ; 36 For(i,1,n) seg[i].s = read() , seg[i].t = read() ; 37 sort(seg+1,seg+n+1,cmp) ; 38 39 int id ; 40 For(i,1,n) 41 if(i==1 || seg[id].t<=seg[i].s ) ans++,id=i ; 42 printf("%d ",ans) ; 43 return 0 ; 44 }