传送门:
思路:一道杂技题....证明杂技,写的也杂技,13年最神的题
首先有一个结论
设S为+1和-1的总和,记sum为后缀和(为什么是后缀?因为做的时候要判后面是还否有解)
如果S!=0,那么ans=ceil(S/m)
否则如果sum[i]==0的个数>=m则为0,否则为1
证明及具体做法见一个详细的题解
deque是不能用的....
#include#include #include #include #include #define min(x,y) ((a[x])<(a[y])?(x):(y))#define abs(a) (a>=0?a:-(a))const int maxn=500010;using namespace std;int n,m,a[maxn],tot,sum[maxn],cnt[maxn];char ch;void read(int &x){ for (ch=getchar();!isdigit(ch);ch=getchar()); for (x=0;isdigit(ch);ch=getchar()) x=x*10+ch-'0';}struct node{int l,r,x;}line[maxn<<1];struct Tline{ int head,tail,len; Tline(){head=tail=len=0;} bool empty(){return !len;} int newnode(int l,int r,int x){line[++tot]=(node){l,r,x};return tot;} int front(){return line[head].x;} int back(){return line[tail].x;} void pop_back(){tail=line[tail].l,len--;} void pop_front(){head=line[head].r,len--;} void push_back(int x){ if (!len) head=tail=newnode(0,0,x); else line[tail].r=newnode(tail,0,x),tail=line[tail].r; len++; } void push(int x){ while (len&&a[back()]>a[x]) pop_back(); push_back(x); }}Q[maxn<<1],Qu[maxn<<1],*q=Q+maxn,*qu=Qu+maxn;//是后缀和为i的单调队列,存有哪些点的后缀和为ivoid work(){ int S=sum[1],d=S?(abs(S)-1)/m+1:cnt[1] =m-i;j++) if (!sum[j+1]) q[0].push(j); printf("%d ",a[q[0].front()]); q[0].pop_front(); } } else{ for (int i=2;i<=n;i++) qu[sum[i]].push_back(i-1); int last=0;a[n+1]=n+1; for (int i=1;i d) continue; for (;!qu[j].empty()&&n-qu[j].front()>=m-i;qu[j].pop_front()) if (qu[j].front()>last) q[j].push(qu[j].front()); for (;!q[j].empty()&&q[j].front()<=last;q[j].pop_front()); if (!q[j].empty()) ans=min(ans,q[j].front()); } last=ans,printf("%d ",a[ans]); } } printf("%d\n",a[n]);}int main(){ read(n),read(m); for (int i=1;i<=n;i++) read(a[i]),read(sum[i]),sum[i]=sum[i]?1:-1; for (int i=n-1;i>=1;i--) sum[i]+=sum[i+1]; for (int i=n;i>=1;i--) cnt[i]=cnt[i+1]+(!sum[i]); work(); return 0;}/*8 32 13 14 11 05 06 17 18 0*/