1 #include<cstdio> 2 #include<iostream> 3 #include<cstring> 4 #include<cmath> 5 #include<algorithm> 6 #define ll long long 7 #define M 50009 8 using namespace std; 9 struct data 10 { 11 ll l,r,a,b,id; 12 }da[M]; 13 ll s,n,m,c[M],block,ku,pos[M],su[M]; 14 bool cmp(data a1,data a2) 15 { 16 if(pos[a1.l]==pos[a2.l]) 17 return a1.r<a2.r; 18 return pos[a1.l]<pos[a2.l]; 19 } 20 bool cmp1(data a1,data a2) 21 { 22 return a1.id<a2.id; 23 } 24 ll sqr(ll a1) 25 { 26 return a1*a1; 27 } 28 void up(int a1,int a2) 29 { 30 if(a1) 31 { 32 s-=sqr(su[c[a1]]); 33 su[c[a1]]+=a2; 34 s+=sqr(su[c[a1]]); 35 } 36 return; 37 } 38 ll gcd(ll a1,ll a2) 39 { 40 ll a3=a1%a2; 41 for(;a3;) 42 { 43 a1=a2; 44 a2=a3; 45 a3=a1%a2; 46 } 47 return a2; 48 } 49 int main() 50 { 51 scanf("%lld%lld",&n,&m); 52 for(int i=1;i<=n;i++) 53 scanf("%lld",&c[i]); 54 for(int i=1;i<=m;i++) 55 { 56 scanf("%lld%lld",&da[i].l,&da[i].r); 57 da[i].id=i; 58 } 59 block=(int)sqrt(n); 60 ku=n/block; 61 if(n%block) 62 ku++; 63 for(int i=1;i<=n;i++) 64 pos[i]=(i-1)/block+1; 65 sort(da+1,da+m+1,cmp); 66 int h=0,t=0; 67 for(int i=1;i<=m;i++) 68 { 69 for(;t<da[i].r;t++) 70 up(t+1,1); 71 for(;t>da[i].r;t--) 72 up(t,-1); 73 for(;h<da[i].l;h++) 74 up(h,-1); 75 for(;h>da[i].l;h--) 76 up(h-1,1); 77 if(da[i].l==da[i].r) 78 { 79 da[i].a=0; 80 da[i].b=1; 81 continue; 82 } 83 ll len=da[i].r-da[i].l+1; 84 da[i].a=s-len; 85 da[i].b=len*(len-1); 86 ll k=gcd(da[i].a,da[i].b); 87 da[i].a/=k; 88 da[i].b/=k; 89 } 90 sort(da+1,da+m+1,cmp1); 91 for(int i=1;i<=m;i++) 92 printf("%lld/%lld\n",da[i].a,da[i].b); 93 return 0; 94 }
莫对算法经典例题，按分块排序后暴力。
