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主题链接:http://115.28.76.232/problem?
pid=1427
Let us consider the sequence a1, a2,..., an of non-negative integer numbers. Denote as ci,j the number of occurrences of the number i among a1,a2,..., aj. We call the sequence k-nice if for all i1<i2 and for all j the following condition is satisfied: ci1,j ≥ ci2,j ?k.
Given the sequence a1,a2,..., an and the number k, find its longest prefix that is k-nice.
10 1 0 1 1 0 2 2 1 2 2 3 2 0 1 0
8 0
用线段树维护 0到A[i]-1间的最小值。用F[A[i]] 统计频率。推断 0 到 A[i]-1范围内的最小值与F[A[i]]-K的大小就可以。
//#pragma comment(linker, "/STACK:36777216") #include <functional> #include <algorithm> #include <iostream> #include <fstream> #include <sstream> #include <iomanip> #include <numeric> #include <cstring> #include <climits> #include <cassert> #include <complex> #include <cstdio> #include <string> #include <vector> #include <bitset> #include <queue> #include <stack> #include <cmath> #include <ctime> #include <list> #include <set> #include <map> using namespace std; #define LL long long #define MAXN 200100 struct Node{ int left,right,v; };Node Tree[MAXN<<2]; void Build(int id,int left,int right){ Tree[id].v=0; Tree[id].left=left; Tree[id].right=right; if(left==right) return; int mid=(left+right)>>1; Build(id<<1,left,mid); Build(id<<1|1,mid+1,right); } void Update(int id,int pos,int add){ int left=Tree[id].left,right=Tree[id].right; if(left==right){ Tree[id].v+=add; return; } int mid=(left+right)>>1; if(mid>=pos) Update(id<<1,pos,add); else Update(id<<1|1,pos,add); Tree[id].v=min(Tree[id<<1].v,Tree[id<<1|1].v); } int Query(int id,int Qleft,int Qright){ int left=Tree[id].left,right=Tree[id].right; if(left>=Qleft && right<=Qright) return Tree[id].v; int mid=(left+right)>>1; if(mid>=Qright) return Query(id<<1,Qleft,Qright); else if(mid<Qleft) return Query(id<<1|1,Qleft,Qright); int r1=Query(id<<1,Qleft,Qright),r2=Query(id<<1|1,Qleft,Qright); return min(r1,r2);; } int A[MAXN]; int F[MAXN]; int main(){ int N,K; while(~scanf("%d%d",&N,&K)){ for(int i=1;i<=N;i++) scanf("%d",&A[i]); Build(1,0,N); memset(F,0,sizeof(F)); int i; for(i=1;i<=N;i++){ F[A[i]]++; Update(1,A[i],1); if(A[i]==0) continue; int ans=Query(1,0,A[i]-1); if(ans<F[A[i]]-K) break; } printf("%d\n",i-1); } }
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原文地址:http://www.cnblogs.com/yxwkf/p/4719905.html