NEU 1253 线段树

题目描述：

   Do you know LiuJishou? He is a man who is famous of evaluting netizens' appearance on Sina Weibo. One day, LZ wants to simulate LiuJishou and he evalutes N(1<=N<=50,000) girls appearance. The girls are numbered from 1 to N and LZ gives each girl a score(1<=score<=1,000,000).

    LZ is a shy man and he isn't willing to tell his friends the scores of the girls directly, but LZ allows his friend askes him Q (1<=Q<=200,000) questions. Each question has two integers A and B. LZ will tell his friend the difference between the heightest score and the lowest score in the girls whose are numbered from A to B.

    简单的并查集，记录下最小跟最大就OK 了。

#include <stdio.h>#include <stdlib.h>#include <memory.h> #define N 50010 typedef struct{    long l,r,max_num,low_num;   }Node;long score[N];long n,q;Node node[3*N];long max(long a,long b){    return a > b? a:b;}long min(long a ,long b){    return a < b?a:b;}void init(){    memset(node,0,sizeof(node));    memset(score,0,sizeof(node));}void Build(long left,long right,int t){    long mid = (left+right)/2;    node[t].l = left;    node[t].r = right;    if(left == right){        node[t].low_num = node[t].max_num = score[left];    }else{        Build(left,mid,t*2);        Build(mid+1,right,t*2+1);        node[t].low_num = min(node[t*2].low_num,node[t*2+1].low_num);        node[t].max_num = max(node[t*2].max_num,node[t*2+1].max_num);    }}long Query(long left,long right,long t,int flag){    long mid;    if(left==node[t].l && right == node[t].r)        if(flag == 0)            return node[t].low_num;        else            return node[t].max_num;    if(right<=node[t*2].r)        return Query(left,right,t*2,flag);    if(left >= node[t*2+1].l)        return Query(left,right,t*2+1,flag);    mid = (node[t].l+node[t].r)/2;    if(flag == 1)        return max(Query(left,mid,t*2,1),Query(mid+1,right,t*2+1,1));    else        return min(Query(left,mid,t*2,0),Query(mid+1,right,t*2+1,0));}int main(){    int iCase;    long i,k;    long a,b;    scanf("%d",&iCase);    for(k = 1;k <= iCase;k++){        //init();         scanf("%ld %ld",&n,&q);        for(i = 1;i <= n;i++)            scanf("%ld",&score[i]);        Build(1,n,1);        printf("Test case #%d:\n",k);        for(i = 0;i < q;i++){            scanf("%ld %ld",&a,&b);            printf("%ld\n",Query(a,b,1,1) - Query(a,b,1,0));        }    }    return 0;}/**************************************************************    Problem: 1253    User: ipqhjjybj    Language: C++    Result: 正确    Time:216 ms    Memory:3320 kb****************************************************************/