60 lines
1.1 KiB
C++
60 lines
1.1 KiB
C++
#include<iostream>
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#include<cstdio>
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#include<algorithm>
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#include<cstring>
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using namespace std;
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int n,k,l,r,m,tn,temp,t,M,ss;
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int f[200001][18];
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int lg[200001];
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void pre_rmq()
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{
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for(int j=1;(1<<j)<=n;j++)
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{
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for(int i=1;i+(1<<j)-1<=n;i++)
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f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]);
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}
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}
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int find(int x,int y)
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{
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t=lg[y-x+1];
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return max(f[x][t],f[y-(1<<t)+1][t]);
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}
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bool check(int k)
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{
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tn=n/k*k;
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temp=0;
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for(int i=1;i<=tn;i=i+tn/k)
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temp+=find(i,i+tn/k-1);
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if(temp>=M+1) return 1;
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return 0;
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}
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int main()
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{
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for(int i=2;i<=200000;i++)
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lg[i]=lg[i>>1]+1;
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while(scanf("%d%d",&n,&M)!=EOF)
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{
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ss=0;
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if(n==-1&&M==-1) break;
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for(int i=1;i<=n;i++)
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{
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scanf("%d",&f[i][0]);
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ss+=f[i][0];
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}
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if(ss<=M)
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{
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printf("-1\n");
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continue;
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}
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pre_rmq();
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l=1;r=n;
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while(l<=r)
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{
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m=(l+r)>>1;
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if(check(m)) r=m-1;
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else l=m+1;
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}
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printf("%d\n",l);
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}
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}
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