luogu P3865 【模板】ST表

复习。。。

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int lg[N],f[N][20];
inline int get_max(int l,int r){
    int t=lg[r-l+1];
    return max(f[l][t],f[r-(1<<t)+1][t]);
}
int main(){
    int n,m;
    scanf("%d%d",&n,&m);
    int temp=2;lg[1]=0;
    for(register int i=2;i<=n;++i){
        lg[i]=lg[i-1];
        if(i>=temp)lg[i]++,temp<<=1;
    }
    for(register int i=1;i<=n;++i){
        int t;scanf("%d",&t);
        f[i][0]=t;
    }
    for(register int j=1;j<20;++j){
        for(register int i=1;i+(1<<j)-1<=n;++i){
            f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]);
        }
    }
    for(register int i=1;i<=m;++i){
        int l,r;
        scanf("%d%d",&l,&r);
        printf("%d\n",get_max(l,r));
    }
    return 0;
    
}

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转载于:https://www.cnblogs.com/Dream-Runner/p/10134085.html