69 lines
1.1 KiB
C++
69 lines
1.1 KiB
C++
#include<cstdio>
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#include<cstdlib>
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#include<cstring>
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#include<stack>
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#include<vector>
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#include<algorithm>
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using namespace std;
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const int oo=0x3f3f3f3f;
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const int maxn=1005;
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int n;
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int a[maxn],f[maxn],vis[maxn];
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vector<int> G[maxn];
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void dfs(int u,int c)
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{
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if(vis[u]!=-1&&vis[u]!=c) { printf("0\n"); exit(0); }
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if(vis[u]!=-1) return;
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vis[u]=c;
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for(int i=0;i<G[u].size();i++) dfs(G[u][i],c^1);
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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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scanf("%d",&n);
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for(int i=1;i<=n;i++) scanf("%d",&a[i]);
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f[n+1]=oo;
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for(int i=n;i>=1;i--) f[i]=min(f[i+1],a[i]);
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for(int i=1;i<n;i++)
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for(int j=i+1;j<n;j++)
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if(f[j+1]<a[i]&&a[i]<a[j])
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{
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G[j].push_back(i);
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G[i].push_back(j);
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}
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memset(vis,-1,sizeof(vis));
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for(int i=1;i<=n;i++) if(vis[i]==-1) dfs(i,1);
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stack<int> s1,s2;
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int now=1;
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for(int i=1;i<=n;i++)
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{
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if(vis[i]==1)
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{
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printf("a ");
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s1.push(a[i]);
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}
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else
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{
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printf("c ");
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s2.push(a[i]);
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}
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while((s1.size()&&s1.top()==now)||(s2.size()&&s2.top()==now))
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{
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if(s1.size()&&s1.top()==now)
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{
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printf("b ");
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s1.pop();
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}
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else
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{
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printf("d ");
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s2.pop();
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}
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now++;
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}
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}
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return 0;
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}
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