Bzoj 1636: [usaco Jan] balanced lineup

Noip is coming. Click basic questions.

Question:

Rmq: give you n numbers and Q queries. The maximum value minus the minimum value in each query [L, R.

The written St.

Code:

#include<iostream>#include<cstdio>#include<algorithm>#include<cstring>//by zrt//problem:using namespace std;typedef long long LL;const int inf(0x3f3f3f3f);const double eps(1e-9);int maxx[50005][20],minn[50005][20];int lg;// [ )int main(){    #ifdef LOCAL    freopen("in.txt","r",stdin);    freopen("out.txt","w",stdout);    #endif    int n,q;    scanf("%d%d",&n,&q);    for(int i=1;i<=n;i++){        scanf("%d",&maxx[i][0]);        minn[i][0]=maxx[i][0];    }    for(lg=0;(1<<lg)<=n;lg++);lg--;    for(int j=1;j<=lg;j++){        for(int i=1;i+(1<<j)<=n+1;i++){            minn[i][j]=min(minn[i][j-1],minn[i+(1<<(j-1))][j-1]);            maxx[i][j]=max(maxx[i][j-1],maxx[i+(1<<(j-1))][j-1]);        }    }    for(int i=0,x,y;i<q;i++){        scanf("%d%d",&x,&y);        int a;        for(a=0;(1<<a)<=y-x+1;a++);a--;        printf("%d\n",max(maxx[x][a],maxx[y-(1<<a)+1][a])-min(minn[x][a],minn[y-(1<<a)+1][a]));    }    return 0;}

Bzoj 1636: [usaco Jan] balanced lineup