C - RMQ with Shifts
Time Limit:1000MS Memory Limit:131072KB 64bit IO Format:%lld
& %llu
Submit Status Practice CSU
1110
Appoint description:
System Crawler (2015-03-10)
Description
In the traditional RMQ (Range Minimum Query) problem, we have a static array A. Then for each query (L, R) (L<=R), we report the minimum value among A[L], A[L+1], …, A[R]. Note that the indices start from 1, i.e. the left-most element is A[1].
In this problem, the array A is no longer static: we need to support another operation shift(i1, i2, i3, …, ik) (i1<i2<...<ik, k>1): we do a left “circular shift” of A[i1], A[i2], …, A[ik].
For example, if A={6, 2, 4, 8, 5, 1, 4}, then shift(2, 4, 5, 7) yields {6, 8, 4, 5, 4, 1, 2}. After that, shift(1,2) yields {8, 6, 4, 5, 4, 1, 2}.
Input
There will be only one test case, beginning with two integers n, q (1<=n<=100,000, 1<=q<=120,000), the number of integers in array A, and the number of operations. The next line contains n positive integers not greater than 100,000, the initial elements
in array A. Each of the next q lines contains an operation. Each operation is formatted as a string having no more than 30 characters, with no space characters inside. All operations are guaranteed to be valid. Warning: The dataset is large, better to use
faster I/O methods.
Output
For each query, print the minimum value (rather than index) in the requested range.
Sample Input
7 5 6 2 4 8 5 1 4 query(3,7) shift(2,4,5,7) query(1,4) shift(1,2) query(2,2)
Sample Output
1 4 6152ms分析:题目中说了a string having no more than 30 characters ,说明每次操作数据量比较小,可以用线段树直接搞,写代码的时候有很多细节要注意,不然就各种wrong,#include <iostream> #include <stdio.h> #include <string> #include <string.h> #include <algorithm> using namespace std; const int MAXN=100010; int n,m; int a[MAXN]; int shift[40]; char s[50]; struct node { int l,r; int minn; }st[MAXN*4]; void build(int v,int l,int r) { st[v].l=l; st[v].r=r; if(l==r) { st[v].minn=a[l]; return ; } int mid=(l+r)/2; build(2*v,l,mid); build(2*v+1,mid+1,r); st[v].minn=min(st[2*v].minn,st[2*v+1].minn); } void update(int v,int id,int key) { if(st[v].l==st[v].r&&st[v].l==id) { st[v].minn=key; return ; } int mid=(st[v].l+st[v].r)/2; if(id<=mid) update(2*v,id,key); else update(2*v+1,id,key); st[v].minn=min(st[2*v].minn,st[2*v+1].minn); } int RMQ(int v,int l,int r) { if(st[v].l==l &&st[v].r==r) return st[v].minn; int mid=(st[v].l+st[v].r)/2; if(r<=mid) return RMQ(2*v,l,r); else if(l>mid) return RMQ(2*v+1,l,r); else { int t1=RMQ(2*v,l,mid); int t2=RMQ(2*v+1,mid+1,r); return min(t1,t2); } } int main() { while(scanf("%d%d",&n,&m)!=EOF) { for(int i=1;i<=n;i++)scanf("%d",&a[i]); build(1,1,n); //cout<<st[1].minn<<endl; while(m--) { scanf("%s",s); if(s[0]=='q') { int l=0,r=0,i,j; for(i=6;s[i]!=',';i++)l=l*10+(s[i]-'0'); for(j=i+1;s[j]!=')';j++)r=r*10+(s[j]-'0'); // cout<<l<<" "<<r<<endl; printf("%d\n",RMQ(1,l,r)); } else { int base=0,ct=0; for(int i=6;s[i]!=')';) { if(s[i]==',') { i++; shift[++ct]=base; base=0; continue; } base=base*10+(s[i]-'0'); i++; } shift[++ct]=base; int tmp=a[shift[1]]; for(int i=2;i<=ct;i++) { a[shift[i-1]]=a[shift[i]]; } a[shift[ct]]=tmp; for(int i=1;i<=ct;i++)update(1,shift[i],a[shift[i]]); } } } return 0; }