bzoj1676[Usaco2005 Feb]Feed Accounting 饲料计算*

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define inc(i,j,k) for(int i=j;i<=k;i++)
 5 #define maxn 10010
 6 using namespace std;
 7 
 8 inline int read(){
 9     char ch=getchar(); int f=1,x=0;
10     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
11     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();
12     return f*x;
13 }
14 int sum[maxn],c,f1,f2,d;
15 int main(){
16     c=read(); f1=read(); f2=read(); d=read();
17     inc(i,1,c){int x=read(),y=read(); sum[x]++; sum[y+1]--;}
18     inc(i,1,d)sum[i]+=sum[i-1];
19     for(int i=d;i>=1;i--){
20         f2+=sum[i]; if(f2==f1){printf("%d",i); return 0;}
21     }
22 }