Description
Farmer John has a collection of wooden planks of length L that he can use to bridge these mud pools. He can overlap planks and the ends do not need to be anchored on the ground. However, he must cover each pool completely.
Given the mud pools, help FJ figure out the minimum number of planks he needs in order to completely cover all the mud pools.
Input
* Lines 2..N+1: Line i+1 contains two space-separated integers: s_i and e_i (0 <= s_i < e_i <= 1,000,000,000) that specify the start and end points of a mud pool along the road. The mud pools will not overlap. These numbers specify points, so a mud pool from 35 to 39 can be covered by a single board of length 4. Mud pools at (3,6) and (6,9) are not considered to overlap.
Output
Sample Input
3 3
1 6
13 17
8 12
Sample Output
5
Hint
FJ needs to use planks of length 3 to cover 3 mud pools. The mud pools cover regions 1 to 6, 8 to 12, and 13 to 17.
OUTPUT DETAILS:
FJ can cover the mud pools with five planks of length 3 in the following way:
111222..333444555....
.MMMMM..MMMM.MMMM....
012345678901234567890
Source
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
const int mxn=;
struct wd{
int x,y;
bool operator < (const wd rhd){
return x<rhd.x;
}
}a[mxn];
int n,L;
int main(){
scanf("%d%d",&n,&L);
int i,j;
for(i=;i<=n;i++){
scanf("%d%d",&a[i].x,&a[i].y);
}
sort(a+,a+n+);
int cnt=;
int now=;
for(i=;i<=n;i++){
now=max(now,a[i].x);//开始铺
while(now<a[i].y){
now+=L;
cnt++;
}
}
printf("%d\n",cnt);
return ;
}