bzoj1689[Usaco2005 Open] Muddy roads 泥泞的路

 1 #include <cstdio>
 2 #include <algorithm>
 3 #include <cstring>
 4 #define maxn 10100
 5 #define inc(i,j,k) for(int i=j;i<=k;i++)
 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 struct rg{int l,r;}; rg rgs[maxn]; int n,l,ans;
15 bool cmp(rg a,rg b){return a.l<b.l;}
16 int main(){
17     n=read(); l=read(); 
18     inc(i,1,n)rgs[i].l=read(),
19     rgs[i].r=read()-1;
20     sort(rgs+1,rgs+1+n,cmp); int i=1;
21     while(i<=n){
22         ans+=(rgs[i].r-rgs[i].l+l)/l; int rem=(rgs[i].r-rgs[i].l+1)%l; if(rem)rem=l-rem;
23         while(i<n&&rem>=rgs[i+1].r-rgs[i].r)rem-=(rgs[i+1].r-rgs[i].r),i++;
24         if(i==n)break; if(rem>=rgs[i+1].l-rgs[i].r)rgs[i+1].l+=rem-(rgs[i+1].l-rgs[i].r)+1;
25         i++;
26     }
27     printf("%d",ans); return 0;
28 }