樹狀數組專題(十二)之hdu2227
//題目大意前面hdu4000處理過三元素的遞增序列.
//這裏要求輸出所有遞增的子序列..
//題目鏈接:http://acm.hdu.edu.cn/showproblem.php?pid=2227
//本來處理情況也可以那樣..但是由於數據太大了.
//開數組要開到2^32.不行..但是數據個數只有100000
//所以有一個新的處理方式..a[] = 1,6,5,2,3
//b[] = 1,2,3,5,6;
//對每個a[]數組元素進行處理的時候..
//在b[]中去搜索本來應該出現的位置..然後更新這個位置
//這樣就可以滿足在a[i]後面的比a[i]大的能夠進行Getsum的準確處理.
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<iostream>
#include<string.h>
#include<vector>
#include<algorithm>
using namespace std;
const int MN = 100004;
const int mn = 1000000007;
int a[MN],b[MN],c[MN];
__int64 tree[MN],dp[MN];
int Lowbit(int x)
{
return x&(-x);
}
__int64 Getsum(int x)
{
__int64 sum = 0;
while(x)
{
sum = (sum + tree[x])%mn;
x -= Lowbit(x);
}
return sum;
}
void Updata(int x, int value)
{
for(int i = x ; i <= MN; i += Lowbit(i))
{
tree[i] = (tree[i]+value)%mn;
}
}
int m;
int binary(int x)
{
int l = 1 ,r = m;
while(l <= r)
{
int mid = (l+r)/2;
if(b[mid] == x )
{
return mid;
}
if(b[mid] > x)r = mid-1;
if(b[mid] < x)l = mid+1;
}
return -1;
}
int main()
{
int n;
while(scanf("%d",&n) != EOF)
{
memset(dp,0,sizeof(dp));
memset(tree,0,sizeof(tree));
for(int i = 1 ; i <= n ; i++)
{
scanf("%d",&a[i]);
c[i] = a[i];
}
sort(c+1,c+n+1);
m = n;
int t = 1;
for(int i = 1 ; i <= n ; i++)
{
b[t++] = c[i];
int x = i+1;
for(int j = i+1 ; j <= n ; j++)
{
if(c[i] != c[j])
{x = j;break;}
}
i = x-1;
}
m = t-1;
__int64 ans = 0;
for(int i = 1 ; i <= n ; i++)
{
int id = binary(a[i]);
dp[i] = (Getsum(id)+1)%mn;
Updata(id,dp[i]);
}
for(int i = 1 ; i <= n ; i++)
{
// printf("%d ",dp[i]);
ans = (ans+dp[i])%mn;
}
printf("%I64d\n",ans);
}
}
//這裏要求輸出所有遞增的子序列..
//題目鏈接:http://acm.hdu.edu.cn/showproblem.php?pid=2227
//本來處理情況也可以那樣..但是由於數據太大了.
//開數組要開到2^32.不行..但是數據個數只有100000
//所以有一個新的處理方式..a[] = 1,6,5,2,3
//b[] = 1,2,3,5,6;
//對每個a[]數組元素進行處理的時候..
//在b[]中去搜索本來應該出現的位置..然後更新這個位置
//這樣就可以滿足在a[i]後面的比a[i]大的能夠進行Getsum的準確處理.
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<iostream>
#include<string.h>
#include<vector>
#include<algorithm>
using namespace std;
const int MN = 100004;
const int mn = 1000000007;
int a[MN],b[MN],c[MN];
__int64 tree[MN],dp[MN];
int Lowbit(int x)
{
return x&(-x);
}
__int64 Getsum(int x)
{
__int64 sum = 0;
while(x)
{
sum = (sum + tree[x])%mn;
x -= Lowbit(x);
}
return sum;
}
void Updata(int x, int value)
{
for(int i = x ; i <= MN; i += Lowbit(i))
{
tree[i] = (tree[i]+value)%mn;
}
}
int m;
int binary(int x)
{
int l = 1 ,r = m;
while(l <= r)
{
int mid = (l+r)/2;
if(b[mid] == x )
{
return mid;
}
if(b[mid] > x)r = mid-1;
if(b[mid] < x)l = mid+1;
}
return -1;
}
int main()
{
int n;
while(scanf("%d",&n) != EOF)
{
memset(dp,0,sizeof(dp));
memset(tree,0,sizeof(tree));
for(int i = 1 ; i <= n ; i++)
{
scanf("%d",&a[i]);
c[i] = a[i];
}
sort(c+1,c+n+1);
m = n;
int t = 1;
for(int i = 1 ; i <= n ; i++)
{
b[t++] = c[i];
int x = i+1;
for(int j = i+1 ; j <= n ; j++)
{
if(c[i] != c[j])
{x = j;break;}
}
i = x-1;
}
m = t-1;
__int64 ans = 0;
for(int i = 1 ; i <= n ; i++)
{
int id = binary(a[i]);
dp[i] = (Getsum(id)+1)%mn;
Updata(id,dp[i]);
}
for(int i = 1 ; i <= n ; i++)
{
// printf("%d ",dp[i]);
ans = (ans+dp[i])%mn;
}
printf("%I64d\n",ans);
}
}
發表評論
所有評論
還沒有人評論,想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.