BZOJ3790: 神奇项链

  1 #include<cstdio>
  2 
  3 #include<cstdlib>
  4 
  5 #include<cmath>
  6 
  7 #include<cstring>
  8 
  9 #include<algorithm>
 10 
 11 #include<iostream>
 12 
 13 #include<vector>
 14 
 15 #include<map>
 16 
 17 #include<set>
 18 
 19 #include<queue>
 20 
 21 #include<string>
 22 
 23 #define inf 1000000000
 24 
 25 #define maxn 500000+5
 26 
 27 #define maxm 20000000+5
 28 
 29 #define eps 1e-10
 30 
 31 #define ll long long
 32 
 33 #define pa pair<int,int>
 34 
 35 #define for0(i,n) for(int i=0;i<=(n);i++)
 36 
 37 #define for1(i,n) for(int i=1;i<=(n);i++)
 38 
 39 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
 40 
 41 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
 42 
 43 #define mod 1000000007
 44 
 45 using namespace std;
 46 
 47 inline int read()
 48 
 49 {
 50 
 51     int x=0,f=1;char ch=getchar();
 52 
 53     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
 54 
 55     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
 56 
 57     return x*f;
 58 
 59 }
 60 int n,m,a[maxn],f[maxn],p[maxn];
 61 char s[maxn];
 62 struct seg{int k,l,r,mi;}t[4*maxn];
 63 inline void build(int k,int l,int r)
 64 {
 65     t[k].l=l;t[k].r=r;int mid=(l+r)>>1;t[k].mi=inf;
 66     if(l==r){if(!l)t[k].mi=-1;return;}
 67     build(k<<1,l,mid);build(k<<1|1,mid+1,r);
 68 }
 69 inline void pushup(int k)
 70 {
 71     t[k].mi=min(t[k<<1].mi,t[k<<1|1].mi);
 72 }
 73 inline void change(int k,int x,int y)
 74 {
 75     int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
 76     if(l==r){t[k].mi=min(t[k].mi,y);return;}
 77     if(x<=mid)change(k<<1,x,y);else change(k<<1|1,x,y);
 78     pushup(k);
 79 }
 80 inline int query(int k,int x,int y)
 81 {
 82     int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
 83     if(l==x&&r==y)return t[k].mi;
 84     if(y<=mid)return query(k<<1,x,y);
 85     else if(x>mid)return query(k<<1|1,x,y);
 86     else return min(query(k<<1,x,mid),query(k<<1|1,mid+1,y));
 87 }
 88 
 89 int main()
 90 
 91 {
 92 
 93     freopen("input.txt","r",stdin);
 94 
 95     freopen("output.txt","w",stdout);
 96 
 97     while(scanf("%s",s)!=EOF)
 98     {
 99         n=strlen(s);
100         build(1,0,n);
101         for1(i,n)a[i<<1]=s[i-1];
102         m=n;n=2*n+1;
103         int id=0,mx=0;
104         for1(i,n)
105         {
106             if(mx>i)p[i]=min(p[2*id-i],mx-i);
107             while(i-p[i]-1>0&&i+p[i]+1<=n&&a[i-p[i]-1]==a[i+p[i]+1])p[i]++;
108             if(i+p[i]>mx)mx=i+p[i],id=i;
109         }
110         int now=0;
111         for1(i,n)if(i+p[i]>now)
112         {
113             for2(j,now+1,i+p[i])f[j]=2*i-j;
114             now=i+p[i];
115         }
116         for1(i,m)change(1,i,query(1,max(0,(f[i<<1]>>1)-1),i-1)+1);
117         printf("%d\n",query(1,m,m));
118         memset(a,0,sizeof(a));
119         memset(s,0,sizeof(s));
120         memset(p,0,sizeof(p));
121         memset(f,0,sizeof(f));
122     }
123 
124     return 0;
125 
126 }