标签:oid div count using == 二分 data for scanf
这题昨天比赛的时候逗了,后缀想不出来,由于n^2的T了,就没往后缀数组想……并且之后解题的人又说用二分套二分来做。然后就更不会了……
刚才看了题解,唉……原来题讲解n^2的也能够过,然后就……这样了!
#pragma comment(linker, "/STACK:1024000000,1024000000") #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<map> #include<queue> #include<set> #include<cmath> #include<bitset> #define mem(a,b) memset(a,b,sizeof(a)) #define lson i<<1,l,mid #define rson i<<1|1,mid+1,r #define llson j<<1,l,mid #define rrson j<<1|1,mid+1,r #define INF 0x7fffffff #define seed 13131 #define seed1 1313 #define maxn 20005 typedef long long ll; typedef unsigned long long ull; using namespace std; void radix(int *str,int *a,int *b,int n,int m) { static int count[maxn]; mem(count,0); for(int i=0; i<n; i++) ++count[str[a[i]]]; for(int i=1; i<=m; i++) count[i]+=count[i-1]; for(int i=n-1; i>=0; i--) b[--count[str[a[i]]]]=a[i]; } void suffix(int *str,int *sa,int n,int m) //倍增算法计算出后缀数组sa { static int rank[maxn],a[maxn],b[maxn]; for(int i=0; i<n; i++) rank[i]=i; radix(str,rank,sa,n,m); rank[sa[0]]=0; for(int i=1; i<n; i++) rank[sa[i]]=rank[sa[i-1]]+(str[sa[i]]!=str[sa[i-1]]); for(int i=0; 1<<i<n; i++) { for(int j=0; j<n; j++) { a[j]=rank[j]+1; b[j]=j+(1<<i)>=n?0:rank[j+(1<<i)]+1; sa[j]=j; } radix(b,sa,rank,n,n); radix(a,rank,sa,n,n); rank[sa[0]]=0; for(int j=1; j<n; j++) rank[sa[j]]=rank[sa[j-1]]+(a[sa[j-1]]!=a[sa[j]]||b[sa[j-1]]!=b[sa[j]]); } } void calcHeight(int *str,int *sa,int *h,int *rank,int n) //求出最长公共前缀数组h { int k=0; h[0]=0; for(int i=0; i<n; i++) rank[sa[i]]=i; for(int i=0; i<n; i++) { k=k==0?0:k-1; if(rank[i]) while(str[i+k]==str[sa[rank[i]-1]+k]) k++; else k=0; h[rank[i]]=k; } } int a[maxn],sa[maxn],height[maxn],rank[maxn]; char s[maxn]; int main() { //freopen("1.txt","r",stdin); scanf("%s",s); int n=strlen(s); copy(s,s+n,a); suffix(a,sa,n,150); calcHeight(a,sa,height,rank,n); int Max,Min,sum=0; for(int i=1;i<=n/2;i++) { Max=Min=sa[0]; for(int j=1;j<=n;j++) { if(height[j]<i||j==n) { if(Max-Min>=i) sum++; Max=Min=sa[j]; } else { Max=max(Max,sa[j]); Min=min(Min,sa[j]); } } } printf("%d\n",sum); return 0; }
acdream 1430 SETI 后缀数组+height分组
标签:oid div count using == 二分 data for scanf
原文地址:http://www.cnblogs.com/llguanli/p/7359107.html