题解：luogu U37449 Lycanthropy

差分套差分qwq

pushinl说这题思维比较好

其实算是比较简单了

一开始写了假的差分

还是没摆脱单个处理

其实是对每个区间边界进行差分处理，每个区间内部再进行标记差分

正解很好理解

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 const int pls=40001;
 7 int a[20000050];
 8 long long bl, tot;
 9 void change(int l, int r, int val){
10     a[l+pls]+=val;
11     a[r+1+pls]-=val;
12 }
13 int main(){
14     int n,m;
15     scanf("%d%d", &n, &m);
16     for (int i=1; i<=n; ++i){
17         int v, x;
18         scanf("%d%d", &v, &x);
19         change(x-v+1, x, -1);
20         change(x+1, x+v, 1);
21         change(x-3*v+1, x-2*v, 1);
22         change(x-2*v+1, x-v, -1);
23         change(x+v+1, x+2*v, 1);
24         change(x+2*v+1, x+3*v, -1);
25     }
26     for (int i=1; i<=m+pls; ++i){
27         bl+=a[i];
28         tot+=bl;
29         if(i>pls)   printf("%lld ", tot);
30     }
31     printf("\n");
32     return 0;
33 }

 

转载于:https://www.cnblogs.com/Aze-qwq/p/9892076.html