【bzoj1828/Usaco2010 Mar】balloc 农场分配——贪心+差分+优先队列

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #include<queue>
 5 const int N=1e5+10;
 6 int n,m,a[N],p[N];
 7 struct node{int l,r;}e[N];
 8 bool cmp(node aa,node bb){return aa.l<bb.l;}
 9 int read(){
10     int ans=0,f=1;char c=getchar();
11     while(c<‘0‘||c>‘9‘){if(c==‘-‘)f=-1;c=getchar();}
12     while(c>=‘0‘&&c<=‘9‘){ans=ans*10+c-48;c=getchar();}
13     return ans*f;
14 }
15 std::priority_queue<int>q;
16 int main(){
17     n=read();m=read();
18     for(int i=1;i<=n;i++)a[i]=read();
19     for(int i=1;i<=m;i++){
20         int l=read(),r=read();e[i]=(node){l,r};
21         p[l]++;p[r+1]--;
22     }
23     std::sort(e+1,e+1+m,cmp);
24     int now=0,h=1;int ans=m;
25     for(int i=1;i<=n;i++){
26         now+=p[i];
27         while(h<=m&&e[h].l==i)q.push(e[h].r),h++;
28         while(now>a[i]&&!q.empty()){
29             int pp=q.top();q.pop();
30             p[pp+1]++;now--;ans--;
31         }
32     }
33     printf("%d\n",ans);
34     return 0;
35 }
36