72 lines
1.0 KiB
C++
72 lines
1.0 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<algorithm>
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using namespace std;
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int n,a[100],lim,up[100],cu,down[100],cd;
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bool dfs(int d)
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{
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if(cu+cd>lim) return false;
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if(d==n) return true;
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int idx=-1;
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for(int i=0;i<cu;i++) if(a[d]>up[i])
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{
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if(idx==-1) idx=i;
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else if(up[i]>up[idx]) idx=i;
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}
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if(idx>-1)
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{
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int bk=up[idx];
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up[idx]=a[d];
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if(dfs(d+1)) return true;
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up[idx]=bk;
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}
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else
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{
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up[cu++]=a[d];
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if(dfs(d+1)) return true;
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cu--;
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}
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idx=-1;
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for(int i=0;i<cd;i++) if(a[d]<down[i])
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{
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if(idx==-1) idx=i;
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else if(down[i]<down[idx]) idx=i;
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}
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if(idx>-1)
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{
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int bk=down[idx];
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down[idx]=a[d];
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if(dfs(d+1)) return true;
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down[idx]=bk;
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}
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else
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{
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down[cd++]=a[d];
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if(dfs(d+1)) return true;
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cd--;
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}
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return false;
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}
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inline int solve()
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{
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for(int i=1;i<=n;i++)
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{
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lim=i;
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cu=cd=0;
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if(dfs(0)) return i;
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}
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return n;
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}
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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while(scanf("%d",&n),n)
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{
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for(int i=0;i<n;i++) scanf("%d",&a[i]);
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printf("%d\n",solve());
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}
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return 0;
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}
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