POJ3264

来源：互联网发布：外贸网站建设推广优化编辑：程序博客网时间：2024/05/22 04:59
#include<stdio.h>#include<stdlib.h>#include<math.h>#include<string.h>#define N 200222int maxc[N][40],minc[N][40],a[N],n,m;int ifmax(int a,int b){        if(a>b)                return a;        return b;}int ifmin(int a,int b){        if(a<b)                return a;        return b;}int logg(int x){        int cnt=-1;        while(x)        {                cnt++;                x=x>>1;        }        return cnt;}void QWER(){        int i,j;        for(i=1;i<=n;i++)        {                maxc[i][0]=a[i];                minc[i][0]=a[i];        }        for(j=1;j<=logg(n);j++)                for(i=1;i+(1<<j)-1<=n;i++)        {                maxc[i][j]=ifmax(maxc[i][j-1],maxc[i+(1<<(j-1))][j-1]);                minc[i][j]=ifmin(minc[i][j-1],minc[i+(1<<(j-1))][j-1]);        }}int main(){        //freopen("in","r",stdin);        int i,da,di,x,y,k;        while(scanf("%d%d",&n,&m)!=EOF)        {                memset(minc,1<<30,sizeof(minc));                memset(maxc,-(1<<30),sizeof(maxc));                for(i=1;i<=n;i++)                        scanf("%d",&a[i]);                QWER();                for(i=0;i<m;i++)                {                        scanf("%d%d",&x,&y);                        k=logg(y-x+1);//这里一开始没注意                        da=ifmax(maxc[x][k],maxc[y+1-(1<<(k))][k]);                       di=ifmin(minc[x][k],minc[y+1-(1<<(k))][k]);                        printf("%d\n",da-di);                }        }        return 0;}
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